Berry Chemistry Form 4

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Berry Chemistry Form 4 Definition List

y BerryBerryTeacher on 28/10/2009

n Berry Reference (Notes)

his is a list of your berry important definitions for SPM Form 4 Chemistry. Try and understand

hem, rather than memorising them. There is no need to memorisation with the understandingf terms.

hemistry Form 4 Definition List

1. Element a substance consists of one type of atom.

2. Compound a substance consists two or more elements that are chemically bonded

(molecule or ions).

3. Atom smallest particle of an element.

4. Molecule a group of two or more atoms.

5. Ion a positively charged / negatively charged particle.6. Isotopes atoms of the same element with same proton number but different nucleon

numbers.

7. Relative atomic mass of an element = the average mass of one atom of an element/

((1/12) x the mass of one carbon-12 atom)

8. Relative molecular mass of an element = the average mass of one atom of an

molecule/((1/12) x the mass of one carbon-12 atom)

9. Molecule formula compound shows the actual number of atoms of each element that

are present in a molecule of the compound

10. Empirical formula compound shows the simplest whole number ratio of atoms of

each element in the compound

11. Mole amount of substance that contains as many particles as the number of atoms in

exactly 12 g of carbon-12 the symbol of mole is mol.

12. One mole Avogadro constant 6.02 x 1023

13. Group (Periodic Table) vertical columns of element (similar chemical properties).

14. Periods (Periodic Table) horizontal rows of element.

15. Valence electrons electrons that occupy the outermost shell.

16. Ionic bond bond formed through the transfer of electrons between atoms of metal and

non-metal to achieve the stable octet electron arrangement.

17. Ionic compound consist of positive ions and negative ions which are held by strongelectrostatic forces of attraction.

18. Covalent bond bond formed through the sharing of non-metal electrons to achieve

the stable duplet or octet electron arrangement.

19. Covalent compound (also simple molecular structure) consists of neutral molecules

which are held by weak intermolecular forces (Van der Waals).

20. Alkali (base) chemical substance which ionizes in water to produce hydroxide ions,

OH-.

21. Acid chemical substance which ionizes in water to produce hydrogen ions, H+ or

hydroxonium ions, H3O+.

22. pH degree of acidity or alkalinity of a solution. Scale ranges from 0 to 14.

23. pH value measure of the concentration of hydrogen ions, H+.

24. Strong alkali ionises (dissociates) completely in water to form hydroxide ions, OH- of

high concentration.
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25. Weak alkali ionises (dissociates) partially in water to form hydroxide ions, OH- of low

concentration.

26. Strong acid ionises (dissociates) completely in water to form hydrogen ions, H+ of

high concentration.

27. Weak acid ionises (dissociates) partially in water to form hydrogen ions, H+ of low

concentration.

28. Polymer long chain molecules made up by monomer (repeating unit).

o there you go!!! 28 of the most common definitions for SPM Form 4 Chemistry.

SPM Chemistry Form 4 Notes

Terminology and Concepts: Introduction

to Chemistry



or those taking science stream in Form 4, Chemsitry will be a new subject that are most likely

within your subject combination choices. It might seemed difficult in the beginning. You might

ven hear stories from seniors about how chemistry gives you sleepless nights. Or stories of

xploding chemicals. Dont fret, chemistry is not all too bad if everybody is attentive to their

eachers and observe lab safety regulations. Berry Berry Easy would like to share with all

Berry Readers the introduction to chemistry. Berry Berry Teacher has decided to make it

ery short so that students do not feel overwhelmed by new things. If you can fully understand

what is written below, then you are cut out to do chemistry.

PM Form 4 Notes Terminology and Concepts: Introduction to Chemistry

hemistry and Its Importance

hemistry earlier study of alchemy (an art of transforming common metals to precious

metals, usually lead to gold but to no success) (alchemy has since been proven to be a wrong

nd currently dead branch of science)

hemistry is the study of the composition, structure, properties and interactions of matter.

ounder of Modern Chemistry (try and read up on the history of these two great men)

1. Robert Boyle (1627-1691) performed controlled experiments and published his work

with elaborate details such as procedure, apparatus and observations.2. Antoine Lavoisier (1743-1794) developed the Law of Conservation of Mass and the

theory of combustion.

cientific Method


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1. Making Observation

2. Making Inference (smart guess)

3. Identifying the Problem

4. Making a Hypothesis

5. Identifying the Variables

6. Controlling the Variables

7. Planning an Experiment

8. Collecting Data

9. Interpreting Data10. Making a Conclusion

11. Writing a Report

you observe all 11 steps, you will be a young scientist in the making. Try to enjoy the process

f learning chemistry. Berry Berry Important subject if you intend to further your career in

he field of engineering.


Terminology and Concepts: The Structure

of the Atom



mong the most basic knowledge in chemistry would be understanding the structure of atom.

he understanding of terms and concepts of all the important keywords and key phrases would

e crucial in gaining further knowledge in chemistry. Fortunately, the structure of atoms has

een simplified for SPM Form 4 students to make it less abstract and more intuitive for

tudents to understand them. It will also be helpful to start to memorise the periodic table for

ow. (If there as anything that you should memorise, it should be the periodic table. As it could

ave you more time in the long run) Nonetheless, Berry Berry Teacher hopes that everybody

ry to understand at minimum the following concepts as terminology before moving on to other

opics.

PM Form 4 Terminology and Concepts: The Structure of the Atom

mportant Terms

Matter anything that occupies space and has mass.

ompound a substance consists two or more elements that are chemically bonded

molecule or ions).

lement a substance that cannot be made into anything simpler by chemical reaction.

Atom smallest particle of an element.

Molecule a group of two or more atoms.

on a positively charged / negatively charged particle.


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ations positively-charge ions. Example: H+, K+, NH4+ and Mg2+

Anions negatively-charge ions. Example: Br-, OH-, O2- and S2O32-

Velocity of the particle increases when

Temperature increases Kinetic energy increases

Diffusion movement of particles from a region of high concentration to a region of low

oncentration.

hanges in the States of Matter

1. Freezing / Solidification liquid -> solid2. Melting solid -> liquid

3. Evaporation liquid -> gas / vapour

4. Condensation gas / vapour -> liquid

5. Sublimation gas / vapour -> solid

6. Sublimation solid -> gas / vapour

Sublimation iodine, ammonium chloride and solid carbon dioxide)

mportant Scientist and Their Contributions

erry Berry Teacher thinks that it will be good if students can link the contribution of each

reat scientists to their findings. This will allow a chronological understanding of the

iscoveries (for easier understanding) and to appreciate the work of these fine scientist.

ohn Dalton (1808) atomic theory

1. Atoms small indivisible particles.

2. Atoms neither created nor destroyed.3. Atoms an element are alike.

4. Atoms it combine in simple ratio.

5. Atoms chemical reactions result from combination / separation of atoms.

J. Thomson (1897)

1. Electrons negatively-charged particles.

2. Atoms positively-charged sphere.

rnest Rutherford (1911)

1. Atoms consists of a positively-charged nucleus with a cloud of electrons surrounding

nucleus.

2. Protons positively-charged particles.


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Niels Bohr (1913)

1. Electrons surrounding the nucleus (orbit).

ames Cadwick (1932)

1. Neutrons electrically neutral subatomic particles.

2. Neutrons mass almost the same with a proton.

3. Nucleus of an atom consists of protons and neutrons.

oncepts of the Atomic Model

Modern Atomic Model

1. Nucleus of an atom consists of protons and neutrons.

2. Electrons moving around the nucleus (orbits / electron shells/ quantum shells)

Proton number / Atomic number / Number of protons

1. Number of protons in its atom.

2. Number of electrons (neutral atom).

Nucleon number / Mass number / Number of nucleon

1. Sum of the number protons and neutrons.

sotopes atoms of the same element with same proton number but different nucleon

umbers.

Further clarification on isotopes as there are still students who are confused with this concept

Isotopes for any elements simply means that it is another element with the same number of

roton and electron but different number of neutrons. It is important to note that the atomic

umber of isotopes are the same, although the mass number is different. If you cannderstand this concept, you should be okay)


Terminology and Concepts: Chemical

Formulae and Equations (Part 1)



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fter few weeks of learning chemistry, there are still some students who wrote in to Berry

Berry Easy to express their problems in mastering chemical formulae and chemical equations.

ome ask if they could just forget about it and catch up later. The answer is NO. Among basic

kills which students must master to understand chemistry, none is more important than

mastering chemical formulae and chemical equations. Most newcomers to the subject of

hemistry are scared off by the rather complex chemical formulae and equations, although

hey become easier when you understand the underlying concept behind them.

hemical formulae are simply there to describe chemical reactions as denoted by the chemical

quations. Confusing? Nay, it should be. Some memorising and practise will go a long way in

nderstanding this topic.

you think this is hard, try understanding the difficulty of chemistry students before Mr

Berzelius devised the current chemical formulae writing system. So give it a try before saying

hat this is hard. For those who do not find this difficult, congratulation. But do work hard in

earning how to express information in a chemical formula properly. So Berry Berry Teacher

would like to share with all some notes as shown below.

PM Form 4 Terminology and Concepts: Chemical Formulae and Equations Part 1

. Relative atomic mass, Ar is the atomic mass of an atom when compared to a standard

tom

. Standard atom:

Hydrogen scale: hydrogen is the lightest atom of all and the mass of one hydrogen atom was

ssigned 1 unit.

Weakness of Hydrogen scale:

not too many elements can react readily with hydrogen, the reactive masses of some elements were not accurate, hydrogen exists as a gas at room temperature and has a number of isotopes with different masses.

Helium scale: the second lightest atom of all and the mass of one helium atom was assigned

unit.

Weakness of Helium scale:

Mass of 1 helium atom = 4 times the mass of a hydrogen atom So, mass of 1 helium atom = 4 times 1/12 mass of a carbon atom helium exists as a gas at room temperature and helium is an inert gas.

Oxygen scale: chose as the standard atom to compare the masses of atoms

Weakness of Oxygen scale:

the existence of three isotopes of oxygen were discovered, natural oxygen (containing all the three isotopes) as the standard (Chemist) and


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used the isotopes oxygen-16 as the standard (Physicists).

arbon scale: standard atom of comparison internationally.

a carbon-12 atom is 12 times heavier than an atom of hydrogen, used as the reference standard in mass spectrometers, exists as a solid at room temperature, most abundant carbon isotope, happening about 98.89% and

carbon-12 is close to the agreement based on oxygen.

. Relative molecular mass, Mr of a substances is the average mass of a molecule (two or

more atoms) of the substances when compared 1/12 with of the mass of a carbon-12 atom.

. Relative formula mass, Fr is for ionic compound which is calculated by adding up the

elative atomic masses of all the atoms.

. Example:

Relative atomic mass, Ar of helium = 4 Relative molecular mass, Mr of CO2 = 12 + 2(16) = 44 Relative formula mass, Fr of NaCl = 23 + 35.5 = 58.5 Relative formula mass, Na2CO310H2O = 2(23) + 12 + 3(16) + 10 [2(1) + 16] = 286

ry to solve some of the examples without looking at the answers. If you can understand this,

hen stay tune and log in again for Part 2 of this topics notes. If you cannot understand the

xamples, try and try and try and try and try again until you are good with it. Till then.

SPM Chemistry Form 4 Notes Terminology and Concepts: Chemical

Formulae and Equations (Part 2)



his is the second part of the notes on Chemical Formulae and Equations that wasosted on Berry Berry Easy some few days back. The first part focused on relative atomic

mass, relative formula mass, relative molecular mass and the various scales from different

tom types. So here we are, moving on to some tougher concepts. Lets us get acquaintant

with Mr Avogadro and see what we can further learn on this topic.

PM Form 4 Terminology and Concepts: Chemical Formulae and Equations (Part 2)

Berry Berry Scientist

alian physicistAmedeo Avogadro (Name at birth: Lorenzo Romano Amedeo Carlo Avogadro)

Born: 9 August 1776 Birthplace: Turin, Piedmont, Italy Died: 9 July 1856


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Best Known As: The guy they named Avogadros number after

. Avogadro constant / Avogadros number is 6.02 x 1023

. Atomic substances

Elements all the particles are atoms. Example: zinc (Zn), sodium (Na), aluminium (Al) and all noble gases, argon (Ar), helium

(He) and neon (Ne). RAM (Relative Atomic Mass) of Na = 23

. Molecular substances

Covalent compounds the particles are molecules. Example: carbon dioxide (CO2), water (H2O) and non-metal elements, iodine (I2), nitrogen

(N2) and oxygen (O2). RMM (Relative Molecular Mass) of I2 = 127 + 127 = 254

. Ionic substances

Ionic compounds the particles are ions. Example: sodium chloride (NaCl), hydrochloric acid (HCl) and potassium iodide (KI). RFM (Relative Formula Mass) of HCl = 1 + 35.5 = 36.5

. Avogadros Law / Gas Law states that equal volumes of all gases contain the same

umber of molecules under the same temperature and pressure.

Example: equal volumes of molecular hydrogen and nitrogen would contain the same

number of molecules under the same temperature and pressure.

. Volume of gas (dm3) = Number of moles of gas x Molar volume

. Room temperature and pressure (r.t.p.) = 24 dm3 mol-1 (25C and 1 atm)

Example: What is the volume of 5.0 mol helium gas at s.t.p.? Volume of gas = Number of moles x Molar gas volume

= 5.0 mol x 24 dm3 mol-1

= 120 dm3

. Standard temperature and pressure (s.t.p.) = 22.4 dm3 mol-1 (0C and 1 atm)

Example: What is the volume of 5.0 mol helium gas at s.t.p.? Volume of gas = Number of moles x Molar gas volume

= 5.0 mol x 22.4 dm3 mol-1

= 112 dm3

. Mass (g) = Number of moles x Molar mass

0. Number of particles = Number of moles x Avogadro constant

1. Volume (dm3) = Number of moles x Molar volume


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e sure to copy down all these formulae a few times on paper so that you will have a better

hance recalling it in the future. Copying them onto a card to bring around will be very helpful.



Formulae and Equations (Part 3)y BerryBerryTeacher on 14/04/2010


Berry Berry Easy would like to present all Form 4 SPM student who took chemistry with the

hird part of the notes on Chemical Formulae and Equations. For those who have

missed out on the previous two parts, do check them out and learn about relative atomic

mass, relative formula mass, relative molecular mass and the various scales from different

tom types, properties (with units) and the very important concept of Standard Temperaturend Pressure (s.t.p). So let us begin on the most difficult topic in Form 4 so far, after the earlier

asy topics.

PM Form 4 Terminology and Concepts: Chemical Formulae and Equations (Part 3)

mpirical and Molecular Formulae

. Empirical (simplest ratio of atoms of each element that present in the compound) and

molecular formulae (actual number of atoms of each element that are present in one molecule

f the compound) indicate:

the types of the elements the symbols of the elements and the ratio of atoms or moles of atoms of each element in a compound.

. Molecular formula = (empirical formula)n

is a positive number

ompound Molecular formula n Empirical formula

arbonoxide

CO2 1 (CO2) = CO2

thane CH3 2 (CH3)2 = C2H6

ropene CH2 3 (CH2)3 = C3H6

lucose CH2O 6 (CH2O)6 = C6H12O6

uinine C10H12NO 2 C20H24N2O2

. Chemical formulae for covalent compounds.

ame Chemicalformula

Number of eachelement

itrogenas

N2 2 nitrogen atoms


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xygen gas O2 2 oxygen atoms

mmonia NH3 1 nitrogen atom and3 hydrogen atoms

Water H2O 2 hydrogen atomsand 1 oxygen atom

. Cations are positively-charged ions.

harge Cations Formula1 Ammonium ion NH4+

1 * Copper(I) ion Cu+

1 Hydrogen ion H+

1 Lithium ion Li+

1 * Nickel(I) ion Ni+

1 Potassium ion K +

1 Silver ion Ag+

1 Sodium ion Na+

2 Barium ion Ba2+

2 Calcium ion Ca2+

2 * Copper(II) ion Cu2+

2 * Iron(II) ion Fe2+

2 * Lead(II) ion Pb2+

2 Magnesium ion Mg2+

2 * Manganese(II) ion Mn2+

2 Nickel(II) ion Ni2+

2 * Tin(II) ion Sn2+

2 Zinc ion Zn2+

3 Aluminium ion Al3+

3 * Chromium(III) ion Cr3+

3 * Iron(III) ion Fe3+

4 * Lead(IV) ion Pb4+

4 * Tin(IV) ion Sn4+

refer to the Roman numerals

. Anions are negatively-charged ions.

harge Anions Formula

1 Bromide ion Br-

1 Chloride ion Cl-

1 Chlorate(V) ion ClO3-

1 Ethanoate ion CH3COO-

1 Fluoride ion F-

1 Hydride ion H-

1 Hydroxide ion OH-

1 Iodide ion I-

1 Manganate(VII) ion MnO4-

1 Nitrate ion NO3-

1 Nitrite ion NO2-


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2 Oxide ion O2-

2 Carbonate ion CO32-

2 Chromate(VI) ion CrO42-

2 Dichromate(VI) ion Cr2O72-

2 Sulphide ion S2-

2 Sulphate ion SO42-

2 Sulphite ion SO32-

2 Thiosulphate ion S2O32-

3 Nitride ion N3-

3 Phosphate ion PO43-

3 Phosphite ion PO33-

. Chemical formulae for ionic compounds

ame Chemicalformula

Numberof cation

Numberof anion

inc chloride ZnCl2 1 Zn2+ 2 Cl-

opper(II)ulphate

CuSO4 2 Cu2+ 2 SO42-

luminiumulphate

Al2(SO4)3 2 Al3+ 3 SO42-

. Meaning of prefixes

refix Meaning

ono- 1

i- 2ri- 3

etra- 4

enta- 5

exa- 6

epta- 7

cta- 8

ona- 9

eca- 10

. Naming of chemical (non-metal) compounds with Greek numerical prefixes.

on-metalompound

Chemicalformula

arbon monoxide CO

arbon dioxide CO2

ulphur dioxide SO2

ulphur trioxide SO3

arbonetrachlorideetrachloromethan)

CCl4


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o, do come back for more Berry Essential Notes. If it is not simplified to its essense, then it

s not from Berry Berry Easy. Let us do the summarising while you understand the core

efore you master the whole topic. Do share out this site with your friends.



Formulae and Equations (Part 4)y BerryBerryTeacher on 28/04/2010


inally after a long wait, the final part (Part 4) of the long series, SPM Chemistry Form 4

otes on Chemical Formulae and Equations is here on Berry Berry Easy. In the first

hree parts, the relative atomic mass, relative formula mass, relative molecular mass, scales,

roperties, Standard Temperature Pressure (s.t.p.), empirical formula, molecular formula,ovalent compounds, ions, ionic compounds and even prefixes were all discussed. All these are

f utmost importance in understanding Chemistry. So all Form 4 students must understand

hem by now if you wish to understand other chapters. (For Form 5 students who have not

mastered the aforementioned concepts, make sure you look back at previous posts and learn

hem before your SPM)

n this part, well try to apply what you have learnt in the previous three parts with some

xamples. So get a pen and paper to follow through the steps. Good revision too if you have

lready understand it.

orm 4 Terminology and Concepts: Chemical Formulae and Equations (Part 4)

hemical Equation

. Importance of chemical equation:

he types of reactants; the physical conditions; the quantity of reactants and products and

tated in moles.

A + nB > pC + pD

. Reactants are written in the left side of the reaction and products are written in the right

ide of the reaction.

Example 1:

Word equation: Sodium hydroxide + sulphuric acid > sodium sulphate + water

Chemical equation: NaOH + H2SO4 > Na2SO4 + H2O

Balancing equation: 2NaOH + H2SO4 > Na2SO4 + 2H2O

Complete chemical equation: 2NaOH + H2SO4 > Na2SO4 + 2H2O Example 2:

Word equation: Aluminium + copper(II) oxide > aluminium(III) oxide + copperChemical equation: Al + CuO > Al2O3 + Cu

Balancing equation: 2Al + 3CuO > Al2O3 + 3Cu

Complete chemical equation: 2Al + 3CuO > Al2O3 + 3Cu Example 3:

Word equation: Nitrogen + hydrogen ammonia


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Chemical equation: N2 + H2 NH3Balancing equation: N2 + 3H2 2NH3Complete chemical equation: N2 + 3H2 2NH3

. Information obtainable from chemical equations.

i) mass of reactants ii) volume of reacting gas

iii) mass of products formed iv) volume of gas produced

Example:

2 cm3 of lead (II) nitrate solution is added to excess of potassium iodide solution.

How many molecules of potassium nitrate will be formed?

[Relative atomic mass: N, 14; O, 16; K, 39; I, 127; Pb, 207; Avogadro's constant: 6.02 x

1023 mol-1]

tep 1: Write a complete chemical equation.

Pb(NO3)2(aq) + 2KI(aq) > PbI2(s) + 2KNO3(aq) From the equation, 1 mole of Pb(NO3)2 reacts with 2 moles of KI formed 1 mole PbI2 of and

2 moles of KNO3.

tep 2: Convert to moles.

No. of moles of Pb(NO3)2= Mass of Pb(NO3)2 / Relative molecular mass

= 2 / [207 + 2(14 + 3 x 16)]

= 6.04 x 10-3 mol

tep 3: Ratio of moles.

Number of moles of KNO3/ Number of moles of Pb(NO3)2= 2/1

Number of moles of KNO3= (2 x 6.04 x 10-3) / 1

= 12.08 x 10-3 mol

tep 4: Convert to the number of molecules of potassium nitrate.

Number of molecules of KNO3= 12.08 x 10-3 x 6.02 x 1023

= 7.27 x 1021

Once you have completed all parts in this series, you would have mastered the most basic of

nowledge in SPM Chemistry. So make sure all Berry Readers understand the basics before

moving on to more advance topics.

SPM Chemistry Form 4 Notes Periodic

Table of Elements (Part 1)


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he Periodic Table (or more accurately, the Periodic Table of Elements) is something all

PM chemistry students love and hate. Maybe more hate than love at first, but usually more

ove than hate towards examination time.As all would know before even learning chemistry, it

s a table to systematically classify and compare all elements and have found extensive usage

n the field of chemistry and beyond.

he elegance of the periodic table has often been understated and often credited to Dmitri

Mendeleev. However, there are more to it before Mendeleev and this first post on Periodic

able of Elements from Berry Berry Easy for SPM Chemistry Form 4 (SPM Kimia

ingkatan 4) attempts to present the precursor and successor to Mendeleevs Periodic table

n a nutshell.

rivia: For those who studied SPM Chemistry many aeons ago, it was in Malay, and we call the

eriodic Table of Elements asJadual Berkala Unsur.

Tips:Actually, this part is more for interest than actually being tested in exams. Typically, this

ubtopic is disregarded except for the occasional multiple choice questions in exams.

However, a true chemistry student should know some history worth the salt of a true chemistry

over. If you love chemistry, you have a chance to do well in exams.)

PM Chemistry Form 4 Notes Periodic Table of Elements (Part 1)

Development of the Periodic Table

eriodic Table

) Antoine Lavoisier (1743 1794) French chemist

Elements were classified into 4 groups Limitation some wrong information (light and heat were consider as elements

) Johann Dobereiner (1780 1849) German chemist
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Elements were classified into groups named as triad (Triad Law relationship between

properties and atomic masses of the elements) Limitation few elements were classified

) John Newlands (1837 1898) British chemist

Elements were arranged horizontally in ascending order of their atomic masses and each

row consisted of 7 elements (Law of Octaves same properties were repeated at every

eight element) Limitation obeyed by the first 17 elements only (from H to Ca)

D) Lothar Meyer (1830 1895) German chemist

Properties of the elements were in a periodic pattern with their atomic masses Similar chemical properties occupied the same relative positions on the curve

) Dmitri Mendeleev (1834 1907) Russian chemist

Elements were arranged in ascending order of their atomic masses Elements with similar chemical properties were placed in a group Gap for undiscovered elements Prediction: gallium, scandium and germanium (discover later) Separate groups for certain elements: transition elements Meedeleevs Periodic Table was used as a basis for the formation of the Periodic Table

) H. J. G. Moseley (1887 1915) British physicist

Elements were arranged horizontally in ascending order proton numbers

Elements with the same number valence electrons same group 18 vertical columns Group 1, Group 2, until Group 18 Alkali metal Group 1 Alkaline earth metal Group 2 Transition elements Group 3 to Group 12 Halogen Group 17 Noble gas Group 18 Horizontal row of the elements period Period 1 2 elements Period 2 and 3 8 elements Period 4 and 5 18 elements Period 6 32 elements Period 7 27 elements Lantanides proton numbers 58 to 71 Actinides proton numbers 90 to 103 Elements (Group 1, 2 and 13) metal Transition elements (Group 3 to 12) metal Elements (Group 15, 16 and 17) non-metal Carbon and silicon (Group 14) non-metal

he next part, Part 2 ofBerry Berry Easys Notes on Periodic Table of Elements for SPM

hemistry students will focus on the relationship between electron arrangement of the

tom of an element to its group and period. Its easy for a Form 5 student when they look

ack but rather difficult for a Form 4 student. So Form 4 students need to pay full attention


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when your teacher is teaching this part, or you can always refer back to Berry Berry Easy for

ur notes.





PM Chemistry Form 4 Students take note (taking note mentally and also copying notes),

his post on Berry Berry Easy is on Part 2 of SPM Chemistry Form 4 Notes on Periodic

able of Elements. This is the proper start of the meat in this chapter as the history in Part 1

s just a taster. Students will get the first feel of chemistry with the periodic table. In this

art, youll learn about electron arrangement of atoms of an element, and the physico-

hemical properties and uses of noble gases (Group 18 elements).

Tips: Draw out the electron arrangements of atoms of elements in a group side by side on a

iece of paper. Then compare them. Then draw it again but put a mockup periodic table beside

our drawing. This way, youll have a mental picture of the electron arranngements, its

osition in the periodic table and their interconnectivity. This tip is provided by a top student

uring his study days, very effective among Berry Berry Teachers students)


Relationship between the electron arrangement of the atom of an element to its

roup and period

The number of valence electrons determines the chemical properties of elements

(group). Elements in the same group have the same number of valence electrons. The number of shells occupied with electrons in an atom determines the period number

of an element.

Group 1 Group 2

eriod 2 Lithium / Li / 2.1 Beryllium / Be / 2.2eriod 3 Sodium / Na /

2.8.1Magnesium / Mg /2.8.2

eriod 4 Potassium / K /2.8.8.1

Calcium / Ca /2.8.8.2

Group 18 elements


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Monoatomic gas

Group 18 elements are known as noble gases (inert chemically and chemicallyunreactive).

Atomic radius (atomic size) increases (going down the group) Helium atom has only one filled electron shell which is 2 electrons (duplet electron

arrangement) The outermost shell of the atoms (Ne, Ar, Kr, Xe and Rn) have 8 electrons (octet electron

arrangement) Atoms of noble gases do not release electrons, accept electrons or share electrons.

lement Electron arrangement of atomelium /e

2

eon / Ne 2.8

rgon / Ar 2.8.8

rypton /r

2.8.18.8

enon / Xe 2.8.18.18.8

adon / Rn 2.8.18.32.18.8

hysical properties

Monoatomic gases Colourless gas at room temperature Insoluble in water Cannot conduct electricity Poor conductors of heat Melting point and boiling point increases (going down the group) atomic size increases

and force of attraction between atoms of each element become stronger

Density of element increases (going down the group)

hemical properties

Chemically inert / not reactive / non-flammable do not gain, lose or share electrons with

other elements
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ses

Helium airships, weather balloons, cool down metals Neon advertising light bulb Argon welding, filled light bulbs Krypton used in laser, filled photographic flash lamps Radon treat cancer

he next part, Part 3 in this series of notes from Berry Berry Easy on the Periodic Table oflements for SPM Chemistry Form 4 students will be focused on Group 1 elements such as

ithium, Sodium, Potassium, Rubidium, Caesium and Francium. They might be volatile but

xtremely important in your studies. So stay tuned.





Group 1 elements, also known as alkali metals are elements that can usually be

emembered by students in the Periodic Table of Elements, simply due to its proximity to the

eft end of the table. (Most students read from left to right, obviously) The following notes in

Berry Berry Easy is Part 3 of SPM Chemistry Form 4 Notes on Periodic Table of

lements. Similar to understanding noble gases (from Part 2), the trends for Group 1 elements

n terms of electron arrangement of atoms, physical properties, chemical properties and

pecifically for this group, safety precautions will be discussed.

Tips: Please follow the safety precaution prescribed by your teacher in handling the alkali

metals (if you were given the chance to do so). The reason is simple, as you will only need to

ee the volatile nature of alkali metals here when they are in contact with water, Brainiacs

ideo on Alkali Metal . After viewing the video, you should have no reasons to not

ollow the safety precautions)

Second Tips: Do try your best to memorise the elements down the group. Read aloud

veryday a few times: Lithium, Sodium, Potassium, Rubidium, Caesium and Francium. If you do

o, youll memorise it without much effort. Thatll be an advantage in exams.)

http://berryberryeasy.com/category/reference/http://video.google.com/videoplay?docid=-2134266654801392897http://berryberryeasy.com/category/reference/http://video.google.com/videoplay?docid=-2134266654801392897


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Alkali metal atom arrangement

Group 1 elements

Group 1 elements are known as alkali metals Atomic radius (atomic size) increases (going down the group) The outermost shell of the atoms (Li, Na, K, Rb, Cs and Fr) have 1 valence electron Good reducing agents Very reactive increases (going down the group) Very electropositive increases (going down the group)

ement Electron arrangement ofatom

thium / Li 2.1

odium / Na 2.8.1

otassium / 2.8.8.1

ubidium /b

2.8.18.8.1

aesium /s

2.8.18.18.8.1

rancium /r

2.8.18.32.18.8.1

hysical properties

Grey solids with shiny silvery surfaces when freshly cut Soft solids at room temperature Good conductors of electricity Good conductors of heat Low melting point and boiling point (compared to heavy metal) Melting point and boiling point decreases (going down the group) atomic size increases

and number of shells occupied with electrons increases / metallic bonding between

atoms becomes weaker & less heat energy is required to overcome the weaker metallic

bonding. Low density (Li, Na and K float on the surface water / Rb, Cs and Fr sink in the water)
http://berryberryeasy.com/wp-content/uploads/2011/03/Group-1-atom-arrangement.jpg


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Density of element increases (going down the group)

hemical properties

Chemically very reactive and react rapidly with oxygen and water vapour in the air (must

be kept in paraffin oil) Reactivity increases (down the group) how easily it can lose one (single) its valence

electron to achieve stable (octet or duplet) electron arrangement

React vigorously with cold water produce alkaline metal hydroxide solutions andhydrogen gas

React with oxygen produce white solid metal oxides and metal oxides can dissolve in

water to form alkaline metal hydroxide solutions React with halogens produce white solid metal halides

afety precautions

Cannot hold with bare hands Wear safety goggles and gloves

No flammable substance nearby Avoid the fire

he next part, Part 4 in this series of notes from Berry Berry Easy on the Periodic Table of

lements for SPM Chemistry Form 4 students will be focused on Group 17 elements or

Halogens such as Fluorine, Chlorine, Bromine, Iodine and Astatine. They are what the Berry

erry Teacher will call, the friendliest group of elements. After you learn this topic, youll

nderstand why.

SPM Chemistry Form 4 Notes PeriodicTable of Elements (Part 4)



Question: What is the friendliest group of elements across the periodic table of elements?

Answer: The Halogen group.

ow you must be wondering why the Berry Berry Teacher, Miss Isabelle Wong calls it the

riendliest group. For those who answered Halogen, congrats. This is due to Halogens typically

ccuring in pairs in natural conditions. As you would have guessed it, Part 4 of Berry Berry

asy notes on SPM Chemsitry Form 4 Periodic Table of Elements is focused on

alogens. Well be looking at the friendly and interesting group ofGroup 17 elements or

Halogens such as Fluorine, Chlorine, Bromine, Iodine and Astatine. The usual suspects

s we learn each group includes the general properties/nature of elements in the group,

hysical properties, chemical properties and safety precautions.

Tips: You should draw out the diatomic molecules and their electron configurations so that

ou can better understand why they typically exist in the form of diatomic molecules. Try to

lso memorise the atomic size as they go down a group. Note whether if it is metallic or non-

metallic. How about their oxidising abilities? If you can answer those and beyond, you would

ave mastered the basic knowledge on halogens.)


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Molecules of Halogen

Group 17 elements

Group 17 elements are known as halogens Exist as diatomic molecules (F2, Cl2, Br2, I2 and At2) Non-metals Atomic radius (atomic size) increases (going down the group) The outermost shell of the atoms (F, Cl, Br, I and At) have 7 valence electrons Good oxidising agents Very reactive decreases (going down the group) Very electronegative decreases (going down the group)

ement Electron arrangement ofatom

uorine / F 2.7

hlorine / Cl 2.8.7

romine / Br2.8.18.7

dine / I 2.8.18.18.7

statine / At 2.8.18.32.18.7

hysical properties

Non-metals Insulators of electricity Poor conductors of heat Low melting point and boiling point Melting point and boiling point increases (going down the group) molecular size

increases / forces of attraction between molecules become stronger & more heat energyis required to overcome the stronger forces of attraction (Van der Waals forces of

attraction between molecules). Colour: F2 (pale yellow gas), Cl2 (greenish-yellow gas), Br2 (reddish-brown liquid),

I2 (purplish-blacksolid) and At2 (black solid rarest naturally occurring element and

extremely radioactive)
http://berryberryeasy.com/wp-content/uploads/2011/03/Molecules-of-Halogen.jpg


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Low density Density of element increases (going down the group) increase in atomic mass

hemical properties

Chemically reactive Reactivity decreases (down the group) how easily it can gain one (single) more valence

electron to achieve stable (octet) electron arrangement

React with water produce two acids React with hot iron produce brown solids iron(III) halides React with sodium hydroxide NaOH solution produce water and two types of sodium

salts (sodium halide and sodium halite(I))

afety precautions

Poisonous gas Wear safety goggles and gloves Handle in the fume cupboard

he next part, Part 5 in this series of notes from Berry Berry Easy on the Periodic Table of

lements for SPM Chemistry Form 4 students will be focused on Elements in a period.

xample will be given across Period 3 which will form your basis of understanding for changes

hat occur when element moves across a period.





What is the trends of elements across a period? This is one of the most often asked question in

hemistry examinations (or pop quizzes). As SPM students are required to know their periodic

able of elements very well, recognising trends of elements across a period is of utmost

mportance. For this Part 5 ofBerry Berry Easy notes on SPM Chemsitry Form 4

Periodic Table of Elements, the changes across period 3 is discussed in detail. Atomic

adius, proton number, electronegativity, phase changes and other changes will be explained

n point form for easy reading. Students are advised to read the previous 4 parts in the series

f notes before proceeding to this post, in order to better understand this part.

Tips: You should draw out the entire Period 3 and then draw the elements based on their size,

olour, electronegativity (use size of negative signs to represent the levels), the phase which is

ppears in (s = solid, g = gas, l = liquid) and all other characteristics. Then paste this figure

hat you have drawn on your desktop. This way youll see it until you have it in the back of

our head.)



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lements: Zinc Copper Lead Magnesium

lements in a period

The Periodic Table 7 periods (Period 1 to Period 7) Proton number increases by one (across a period from left to right) Number of valence electrons of each element increases (across a period from left to

right)

cross Period 3

Atomic radius / atomic size decreases increasing number of electrons / attraction by

nucleus on the valence electrons becomes stronger (pulled closer to the nucleus) Proton number increases positive charge of the nucleus increases Electronegativity (strength to attract electrons towards its nucleus) increases proton

number increases / positive charge of the nucleus increases Change from solid to gas Left solid metals Right non-metals gases

Electropositive / metallic properties decreases Na, Mg, Al (metals): good conductor / Si (semi-metal): weak conductor of electricity / P,

S, Cl (non-metals): cannot conduct electricity Na, Mg (metals): form oxides with basic properties Al (metal): form oxides with both basic and acidic properties = amphoteric oxides Si (semi-metal): forms oxides with acidic properties P, S, Cl (non-metals): forms oxides with acidic properties

ses of semi-metals (metalloids)

Semiconductor (flow in one direction) Microchip
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he next part, Part 5 is the final part in this series of notes from Berry Berry Easy on the

eriodic Table of Elements for SPM Chemistry Form 4 students. The next post which conclude

he entire series of post will be on transition elements.


Table of Elements (Part 6 Final)



onsider this list:Scandium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt,

Nickel, Copper, Zinc, Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium,

hodium, Palladium, Silver, Cadmium, Hafnium, Tantalum, Tungsten, Rhenium, Osmium,

ridium, Platinum, Gold, Mercury, Rutherfordium, Dubnium, Seaborgium, Bohrium, Hassium,

Meitnerium, Darmstadtium and Roentgenium.

Q: What do they have in common?

A: They are all considered as transition elements (or sometimes called as transition metals)

ote that the list above are not the complete list of transition elements.

o now that you know the elements listed above are transition elements, you might be

nterested to know in-depth about them. This post from the Berry Berry Teacher, Miss

sabelle Wong is all about transition elements. Berry Readers will get to learn about the

hysical characteristics of transition elements, their special characteristics and common uses,

ll in the final part, Part 6 of Berry Berry Easy notes on SPM Chemistry Form 4

Periodic Table of Elements. Do note that, you are advised to read the previous parts before

eading this post. Also, you do not need to memorise all the transition elements listed above,

lthough you do need to know the common ones.

Tips: Learn the colours of the coloured ions, and write them with colour pencils. This will

urther reinforce your ability to remember the colours. The colours are important as they are

ypical examination questions, especially on experimental observations. While memorising the

xact properties of each elements is not required at this level, but you will be better off

emembering the general properties of transition elements.)

PM Chemistry Form 4 Notes Periodic Table of Elements (Part 6 Final)

ransition elements

Elements from Group 3 to Group 12 Metals Atomic radius (atomic size) approximately the same Solids with shiny surfaces Very hard (compared to Group 1 and Group 2 metals)

High density Ductile (ability to stretched into wires without breaking) Malleable (ability to be bent into new shape) High tensile strength (ability to stay in their shape without breaking) High melting and boiling points High density


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Good conductors of electricity Good conductors of heat Electronegativity is low but increases (across the series)

4 5 6 7 8 9 10 11 12

c Ti V Cr Mn Fe Co Ni Cu Zn

Zr Nb Mo Tc Ru Rh Pd Ag Cd

a Hf Ta W Re Os Ir Pt Au Hg

c Rf Db Sg Bh Hs Mt Ds Rg Uub

olourful Complex of Transition Elements

pecial characteristics

Form coloured ions (Cu2+: blue / Fe2+: pale green / Fe3+: yellow) Form coloured compound (cobalt chloride crystal: pink) Different oxidation numbers in their compound Useful catalysts (nickel hydrogenation of vegetable oil, copper(II) sulphate

reaction of zinc with dilute sulphuric acid to liberate hydrogen gas, manganese(IV)

oxide decomposition of hydrogen peroxide to liberate oxygen gas, iron Haberprocess, vanadium(V) oxide Contact process, platinum Ostwald process)

Form complex ions (bigger-sized polyatomic ion) (Hexacyanoferrate(III) ion / [Fe(CN)6]3- )

ses

Iron used as steel Chromium coating corroded metals, heat-resisting alloys and make stainless steel Copper making cables, pipes and electrical wires Titanium metal pipes and tanks, wings of supersonic aircraft

o finally we are at the end ofBerry Berry Easy notes on SPM Chemistry Form 4 notes on the

Periodic Table of Elements. Rejoice. This is a simple but heavily tested topic in exams. They

will also return to haunt you in Form 6, foundation studies, A-level and further up. So learn

hem well over here now.
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SPM Chemistry Form 4 Notes Chemical

Bonds (Part 1)



hemical bond is the reason why substances other than chemical elements exists. It is an

ttraction between at least two atoms which then forms chemical substances. Hence this is the

eason why there are more chemical substances in this planet than they are elements. This is a

elatively easy subject but is very fundamental to chemistry that Berry Readers need to

ully understand it, or else hard time follows in the next couple of years leading to SPM. As

uch, Berry Berry Easy will be sharing Part 1 of SPM Chemistry Form 4 notes on

hemical Bonds.

or Part 1, youll be learning about the formation of compounds, stability of noble gases, the

ypes of chemical bonds and how they can form bonds. Make sure you fully understand thisart before moving on to other topics in Chemistry or even other parts in this series of notes.

Tips:Although chemical bonds are drawn typically with two spheres and a rod connecting

hem (as shown in the figure below), it is important to understand now rather than later that,

he rod (or chemical bond) is not a physical object, but rather more like an 'effect' to allow

toms to come together to form substances. The formed substances each will have its own

hysico-chemical properties due to the type of atoms and bond types involved.]

PM Chemistry Form 4 Notes Chemical Bonds (Part 1)

ormation of Compounds

Compounds different elements that chemically bonded together Octet electron arrangement electron arrangement of an atom where the outermost

occupied shell is filled with eight valence electrons Duplet electron arrangement electron arrangement of an atom where a single shell

filled with two valence electrons

xample:

ompound water is hydrogen and oxygen atoms are chemically bonded together.

tability of Noble Gases

Atom of noble gas does not gain, lose nor share electrons with other atoms. Noble gas atoms do not combine with atoms of other elements to form compounds or

with each other to form molecules. Noble gases are chemically unreactive.

Noble gases exist as monoatomic.

hemical Bonds


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hemical Bond

ypes of chemical bonds:

ionic bonds (metal + non-metal) covalent bonds (non-metal + non-metal)

toms of other elements can achieve the stable octet electron arrangement by

transfer of electrons sharing of electrons

he next part, Part 2 of SPM Chemistry Form 4 notes on Chemical Bonds from Berry Berry Easy will be on ionic bonds, ionic

ompounds and the relatively difficult task of predicting the formula of ionic compounds.


Bonds (Part 2)



onic Bond is one of the two main chemical bonds that Berry Readers will learn as a

hemistry SPM student. Ionic bond is simply a bond formed when there are electrostatic

ttraction between two oppositely charged ions. Typically, ionic bonds are formed between a

metal (cation) and non-metal (anion). Bonds with greater difference in the electronegativity

etween the involved atoms will be more ionic.

it is starting to sound confusing for you, fret not! That was just a teaser from Berry Berryasy on ionic bonds, and this post is the Part 2 of SPM Chemistry Form 4 notes on

hemical Bonds. In this part, youll learn about the basics of ionic bonds (definition),

metals and non-metals (and how they form ionic bonds), structure of ionic compound

nd predicting the formula of an ionic compound.
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Tips: Learn to at least recognise that ionic bonds must consist of a metal and non-metal. Try

nd memorise common pairs of ionic compounds after you understand how they are formed.

Draw many many many diagrams of ionic compounds. With these, you should easily master

he basics of ionic bonds.]


Ionic lattice structure

onic Bonds

It is a chemical bond formed from the transfer of electrons from metal atoms to non-

metal atoms Metal atoms donate valence electrons to form positive ions (cations, Mb+) and achieve

the stable duplet or octet electron arrangement of the noble gases Non-metal atoms receive electrons to form negative ions (anions, Xa-) and achieve the

stable duplet or octet electron arrangement of the noble gases Cations and anions are attracted to each other by strong electrostatic force of attraction

xample:

Metal + Non-metal > Ioniccompound

odium + bromine > Sodium bromide

alcium + chlorine > Calcium chloride

thium + oxygen > Lithium oxide

luminium

+ nitrogen > Aluminiumnitride

Metals

Group 1

A lithium atom with an electron arrangement of 2.1 achieves stability after it donates

one valence electron to form a lithium ion, Li+. The electron arrangement of the lithium

ion, Li+, is 2 with stable duplet electron arrangement.
http://berryberryeasy.com/wp-content/uploads/2011/03/Ion-arrangement.jpg


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A sodium atom with an electron arrangement of 2.8.1 achieves stability after it donates

one valence electron to form a sodium ion, Na+. The electron arrangement of the sodium

ion, Na+, is 2.8 with stable octet electron arrangement. A potassium atom with an electron arrangement of 2.8.8.1 achieves stability after it

donates one valence electron to form a potassium ion, K+. The electron arrangement of

the potassium ion, K+, is 2.8.8 with stable octet electron arrangement.

Group 2

A magnesium atom with an electron arrangement of 2.8.2 achieves stability after it

donates two valence electrons to form a magnesium ion, Mg2+. The electron arrangement

of the magnesium ion, Mg2+, is 2.8 with stable octet electron arrangement. A calcium atom with an electron arrangement of 2.8.8.2 achieves stability after it

donates two valence electrons to form a calcium ion, Ca2+. The electron arrangement of

the calcium ion, Ca2+, is 2.8.8 with stable octet electron arrangement.

Group 13

An aluminium atom with an electron arrangement of 2.8.8.3 achieves stability after itdonates three valence electrons to form an alumium ion, Al3+. The electron arrangement

of the aluminium ion, Al3+, is 2.8.8 with stable octet electron arrangement.

Non-metal

Group 15

A nitrogen atom with an electron arrangement of 2.5 achieves stability after it accepts

three valence electrons to form a nitride ion, N3-. The electron arrangement of the nitride

ion, N3-, is 2.8 with stable octet electron arrangement. A phosphorus atom with an electron arrangement of 2.8.5 achieves stability after it

accepts three valence electrons to form a phosphoride ion, P3-. The electron arrangement

of the phosphoride ion, P3-, is 2.8.8 with stable octet electron arrangement.

Group 16

An oxygen atom with an electron arrangement of 2.6 achieves stability after it accepts

two valence electrons to form a oxide ion, O2-. The electron arrangement of the oxide ion,

O2-, is 2.8 with stable octet electron arrangement. A sulphur atom with an electron arrangement of 2.8.6 achieves stability after it accepts

two valence electrons to form a sulphide ion, S2-. The electron arrangement of the

sulphide ion, S2-, is 2.8.8 with stable octet electron arrangement.

Group 17

A fluorine atom with an electron arrangement of 2.7 achieves stability after it accepts

one valence electron to form a fluoride ion, F -. The electron arrangement of the fluoride

ion, F -, is 2.8 with stable octet electron arrangement.

A chlorine atom with an electron arrangement of 2.8.7 achieves stability after it acceptsone valence electron to form a chloride ion, Cl -. The electron arrangement of the chloride

ion, Cl -, is 2.8.8 with stable octet electron arrangement.

Predict the Formula of an Ionic Compound


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Cation Mb+

Anion Xa-

Formula of an ionic compound formed, MaXb

ormulae for ionic compound

etaltom, M

Non-metalatom, X

IonicCompoun

droup 1 Group 15 M3X

roup 1 Group 16 M2X

roup 1 Group 17 MX

roup 2 Group 15 M3X2

roup 2 Group 16 MX

roup 2 Group 17 MX2

roup3

Group 15 MX

roup3

Group 16 M2X3

roup3

Group 17 MX3

ome common ionic compound

Sodium chloride (NaCl) Magnesium oxide (MgO) Calcium sulphide (CaS)

Potassium oxide (K2O) Magnesium fluoride (MgF2)

tructure of ionic compounds

The oppositely-charged ions, Mb+ and Xa- are attracted to each other by a strong

electrostatic force. It form a rigid 3-dimensional lattice structure Formed crystal. Giant ionic lattice.

Berry Important Notes:

n the diagram of ionic compound, always shows

The outermost shells of all ions must achieve a stable duplet or octet electron

arrangement. The charge of each ion must be placed outside the bracket. Label the ions.

n the next part (Part 3) ofBerry Berry Easy notes on Chemical Bonds for SPM Form 4hemistry students, Berry Readers will learn covalent bonds and the non-metals needed to

orm the bonds, the different types of covalent bonds, examples and structure of covalent

ompounds.


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Extra: Pure ionic bonds cannot actually be formed as all ionic compounds have some levels of

ovalent bonding. However, this is not covered in the syllabus, hence it'll only be for your own

eference, in case you do extra reading online and get confused. Hence, the traditional ionic

ond only exist when ionic character > covalent character]


Bonds (Part 3)y BerryBerryTeacher on 30/03/2011


ovalent bond is the second type of chemical bonds that Berry Readers learn in SPM Form

Chemistry. Covalent bonds occurs when electrons are shared between atoms, rather than a

omplete transfer of electrons in ionic bonding. Typically, covalent bonds occur for non-metals

when they bind together due to similar tendency for electrons (usually to gain electrons in the

yllabus). When non-metals gain electrons, they will share electrons in order to fill up theiralence shell, with one of the simplest example being the abundant hydrogen gas. Now that

ou know that covalent bonding is usually with non-metals and it is different from ionic

onding, the Berry Berry Easy notes of Part 3 of Chemical Bonding for SPM Chemistry

orm 4 begins.

his Part 3 focuses on covalent bonds (definition), non-metals (and how they can form covalent

onds), covalent compound formula prediction, structure of covalent compounds and

ome tips on covalent bonding. So take note of the notes from Part 2 (Ionic bonding) and try to

nd parallels from it. This way youll better learn the two tips of bonds.

Tips: In event that you forget how covalent bond works, think of the humble and simplest

ydrogen gas. Why is it a good example, because it is easy to remember. As hydrogen atom

H) each has one valence electron in their first electron shell, they will 'prefer' to have a

econd electron to fill up the first electron shell. If you remember, the first electron shell has a

apacity of 2 electrons. When the first H atom wants a second electron, another H atom also

wants the same thing. As such, both hydrogen atoms will come together (or in chemistry, we

all it 'react') to form H2, a gas compound. Thus, both atoms now 'enjoy' the stability afforded

y full valence shell. So take out your pencil and draw the concept of covalent bonding a few

mes with the hydrogen atoms.]



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Molecules

ovalent Bonds

It is a chemical bond formed from the sharing of valence electrons between non-metal

atoms to achieve the stable duplet of octet electron arrangement. Each shared pair of electrons is as one covalent bond. It produces molecules. Usually the covalent bonds form between non-metal atoms from Group 15, 16 and 17

and sometimes can be formed from Group 14 (carbon and silicon) and hydrogen. Covalent bond can be formed from atoms of the same element and atoms of different

elements.

xample:

on-metal

+ Non-metal

> Covalentcompound

romine + bromine > Bromine (Br2)

itrogen + nitrogen > Nitrogen (N2)

arbon + chlorine > Tetrachloromethane (CCl4)

ydrogen + oxygen > Water (H2O)

ydrogen + nitrogen > Ammonia (NH3)

ypes of covalent bond formed:

Single bond = one pair of electrons shared between two atoms. Double bond = two pair of electrons shared between two atoms. Triple bond = three pair of electrons shared between two atoms.

Non-metal

Group 15
http://berryberryeasy.com/wp-content/uploads/2011/03/Molecules.jpg


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A nitrogen atom with an electron arrangement of 2.5 needs three more electrons to

achieve stable octet electron arrangement after it contribute (through sharing) three

valence electrons to another atom (can be from Group 14, 15, 16, 17). A phosphorus atom with an electron arrangement of 2.8.5 need three more electrons to

achieve stable octet electron arrangement after it contribute (through sharing) three

valence electrons to another atom (can be from Group 14, 15, 16, 17).

Group 16

An oxygen atom with an electron arrangement of 2.6 needs two more electrons to

achieve stable octet electron arrangement after it contribute (through sharing) two

valence electrons to another atom (can be from Group 14, 15, 16, 17). A sulphur atom with an electron arrangement of 2.8.6 need two more electrons to

achieve stable octet electron arrangement after it contribute (through sharing) two

valence electrons to another atom (can be from Group 14, 15, 16, 17).

Group 17

A fluorine atom with an electron arrangement of 2.7 needs one more electron to achievestable octet electron arrangement after it contribute (through sharing) one valence

electron to another atom (can be from Group 14, 15, 16, 17). A chlorine atom with an electron arrangement of 2.8.7 need one more electron to

achieve stable octet electron arrangement after it contribute (through sharing) one

valence electron to another atom (can be from Group 14, 15, 16, 17).

Predict the Formula of a Covalent Compound

Non-metal X atom (valence electron is a) Combine with another non-metal Y atom (valence electron is b) b = simplest ratio (n) and a = simplest ratio (m) Formula of a covalent compound formed, XnYm

xample:

he electron arrangement of atom X is 2.8.6 and atom Y has four valence electrons. Which of

he following is the formula of the compound formed between X and Y?

A) Y4X

B) Y2X

C) YX

D) YX2

olution:

X has 6 valence electrons, it needs to share 2 electrons to achieve the stable octet

electron arrangement. Y has 4 valence electrons, it needs to share 4 electrons to achieve the stable octet

electron arrangement. Therefore, the formula of the covalent compound is X4Y2 = Y2X4 = simplest ratio YX2.

nswer: D

ome common covalent compound


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Hydrogen molecule, H2 (single bond) Chlorine molecule, Cl2 (single bond) Bromine molecule, Br2 (single bond) Fluorine molecule, F2 (single bond) Water molecule, H2O (single bond) Nitrogen trifluoride molecule, NF3 (single bond) Tetrachoromethane / carbon tetrachloride, CCl4 (single bond) Ammonia molecule, NH3 (single bond)

Oxygen molecule, O2 (double bond) Carbon dioxide molecule, CO2 (double bond) Nitrogen molecule, N2 (triple bond) Ethyne molecule, C2H2 (triple bond)

tructure of covalent compounds

Can be simple molecular structure or giant molecular structure. The atoms in the molecule are joined together by strong covalent bond but

intermolecular forces are weak by weak van der Waals forces.

Berry Important Notes:

n the diagram of ionic compound, always shows

The outermost shells of all atoms must achieve a stable duplet or octet electron

arrangement through sharing. The outermost shells of each atom must overlap. Label all atoms clearly.

he next part, Part 4 in Berry Berry Easys notes on Chemical Bonding for SPM Form 4

hemistry will be on the differences between ionic compound and covalent compound (in

erms of particle, electrons, forces, state, melting point, volatility, solubility in water, solubility

n organic solvent, electricity conductor) and also the uses of covalent compound as solvent.

o stay tuned.


Bonds (Part 4 Final)y BerryBerryTeacher on 01/04/2011


Difference between Ionic Compound and Covalent Compound. This is one of the most

ommon questions in tests for SPM Form 4 Chemistry students. (Then again, this is nothing

nusual as comparison based questions are popular in most exams across all subjects.) This

ost, Part 4 ofBerry Berry Easys notes on Chemical Bonds for SPM Form 4 Chemistry

s all about the differences between the two types of compounds. Youll read all about theifferences in terms ofparticles, electrons, forces, state, melting point, volatility,

olubility (in water and organic solvent) and electricity conductor. Also in this post, youll

e given example of common covalent compounds which can be used as solvent.


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Tips: Try your best to understand the differences between ionic compound and covalent

ompound through this table shown below. After understanding it, you should write it in table

orm as shown at least 3 times to fully memorise it by heart. The knowledge in this chapter

orms the basis upon which you will learn chemistry later on in your student life. Learn by

eart also the common covalent compounds used as solvent, especially their names and

pplication. This always appears in objective questions in exams.]

PM Chemistry Form 4 Notes Chemical Bonds (Part 4 Final)

Properties of Ionic and Covalent Compounds

onic Compound

onic Compound ionic bonding is strong electrostatics forces between the oppositely-charged

ons

ovalent Compound

ovalent Compound covalent bonding is strong bonding between the atoms in the molecule
http://berryberryeasy.com/wp-content/uploads/2011/03/Covalent-Bond.jpghttp://berryberryeasy.com/wp-content/uploads/2011/03/Ionic-Bond.jpg


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onic Compound Differences Covalent Compound

ns Particles Molecules

ost or gained Electron Shared

trongectrostatics

orces (Ionicond) betweenhe oppositely-

harged ionsrranged in a 3-Dant crystalttice

Forces Strong (Covalent bond)between the atoms inthe molecule. Weakforces of attractionbetween the molecules

(van der Waals forces)

olid State Gases or volatile liquids

igh Meltingpoint

Low (Simplemolecules)High (Giantmolecules)

igh Meltingpoint

Low (Simplemolecules)High (Giant

molecules)on-volatile Volatility Very volatile (Simple

molecules)Non-volatile(Giant molecules)

issolve in waternd polar solvents

Solubility inwater

Do not dissolve inwater

o not dissolve inrganic solvent

Solubility inorganicsolvent

Dissolve in organicsolvent (ether, alcohol,benzene,tetrachloromethane

and propanone)onductectricity in liquidnd aqueousolution (positivend negative ionsan move freely).annot conductectricity in solid

tate (fixedosition and

annot moveeely).

Electricityconductor

Cannot conductelectricity in any state(no free mobile ions)

Uses of covalent compounds as solvent

Ether solvents in the extraction of chemicals from aqueous solution Alcohol solvents used to make ink and dye because these solvent are volatile Turpentine dissolved paint CFC (chlorofluocarbons) solvents to clean computer circuits board Propanone remove nail varnish

his is the end of the series of notes on Chemical Bonds brought specially to all Form 4 SPM

hemistry students by Berry Berry Easy. Make sure you understand all the posts in this

eries before you proceed to other chapters as this is a very simple but extremely important

hapter, not only for exams but also for general understanding of chemistry as a subject.


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Berry Chemistry Form 4

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Transcript of Berry Chemistry Form 4