Chemistry Science 09 Review!!

Science 10CT00D01

Topics from Science 09Atomic TheorySubatomic CompositionThe Periodic TableChemical BondingNomenclature and Chemical Reactions

Atomic Theory•Major Contributors:

• Dalton, Thomson, Rutherford, Bohr

John DaltonEngland, 1808Atomic Theory which states: An atom cannot be broken

down into smaller parts. Atoms of the same element

are exactly alike. Atoms of different elements

are different. Atoms can combine in

definite whole-number ratios to form compounds.

Dalton Model Diagram: Shading is used in the sphere to show

that it’s solid throughout. Every substance is made up of atomsAtoms are indestructible and indivisibleAtoms can neither be created or destroyed

J.J. ThomsonEngland, 1897Discovery Atoms contain

electrons Thomson found the

charge-to-mass ratio of an electron.

Thomson Model DiagramThis model is referred to as the ‘Plum Pudding model.’ Thomson believed that the atom consisted of a positive sphere (the pudding) with electrons embedded in it (the raisins).

+ +++

++

+

+

++++

+--

-

- -

-

--

--

--

Ernest RutherfordNew Zealand, 1911Discovery Atoms are made up of mostly empty

space Atoms contain a small, dense, positively-

charged nucleus. • Gold Foil Experiment by Ernest Rutherford

• Positively charged radiation directed towards a thin sheet of gold foil

• Odd results: most radiation went through the foil, some scattered at wide angles, and some shot back at him!

+--

-

-

-

-

-

Rutherford’s Model Diagram

+

Empty Space

Dense, positively charged nucleus

Niels BohrDenmark, 1913Discovery: Electrons contain specific

amounts of energy and orbit the nucleus in specific paths, call energy levels

Electrons must gain energy to move to a higher energy level or lose energy to move to a lower energy level

Bohr Model DiagramThe small particles in the center represent the protons and neutrons in the nucleus.

e-e-

e-Nucleus contains protons (+) and neutrons (o)

Electrons exist in energy levels, 2-8-8, then….

Subatomic Composition

•Atoms consist of: • Protons, neutrons, electrons

•Isotopes, ions, anions, cations

Three charges of an atom…

Mass of p & n are ~1000x greater than mass of e (making it insignificant)

First look at the Periodic Table: What do the numbers mean?

H1

0079.1

Atomic Number (p)Atomic Symbol

Ar (Relative At. Mass)For most common isotope, round it off. (For H would be 1 = 1p & 0n)

How many of each are there?

Protons: always the atomic #Electrons: same as p if neutral If -1, has one more e than p If +1, has one less e than p

Neutrons: Depends on isotope For most common, round off the atomic mass to

find the mass number, then use the formula Ar = p + nMass Number = protons + neutrons

Atomic Number

• Number of protons contained in an atom (p)

• Determines the element

• Every element of that kind has the same number of protons

Mass Number• Number of protons

and neutrons in an atom (p + n)

• Can change for various isotopes

Ions• Differing number

electrons (e)• Changes overall

charge• Cations (positive)• Anions (negative)

Isotopes• Differing number

of neutrons (n)• Changes Mass

Number

Isotopes• An isotope is an element that contains a

different number of neutrons and protons. Affects the molar mass of the element Longhand notation

• Element – Mass Number• Carbon – 12• Carbon – 14

Shorthand notation

XMass#

Atomic #

Charge

4126C

The Periodic Table•Layout: families, groups, etc•Trends:

• Atomic number, mass, valence, charge

• Electronegativity, ionization energy, atomic radius, reactivity, metallic property

H He

Li Be B C N O F Ne

Na

Mg Al Si P S Cl Ar

K Ca Se Ti V Cr Mn Fe Co Ni C

u Zn Ga Ge As Se

BrKr

Rb Sr Y Zr N

b Mo Tc Ru Rh Pd

Ag

Cd In Sn S

b Te I Xe

Cs Ba La Hf Ta W Re Os Ir Pt Au

Hg Tl Pb Bi P

oA

tR

n

Fr Ra Ac Rf Db Sg Bh Hs Mt D

s                

Ce Pr Nd

Pm

Sm Eu Gd T

bD

yH

o Er Tm

Yb Lu

Th Pa U Np Pu A

mCm

Bk Cf Es F

mM

dN

o Lr

PERIODS - Similarities: The number of

outer electron shells.

H He

Li Be B C N O F Ne

Na

Mg Al Si P S Cl Ar

K Ca Se Ti V Cr Mn Fe Co Ni C

u Zn Ga Ge As Se

Br Kr

Rb Sr Y Zr N

b Mo Tc Ru Rh Pd

Ag

Cd In Sn S

b Te I Xe

Cs Ba La Hf Ta W Re Os Ir Pt Au

Hg Tl Pb Bi P

oAt

Rn

Fr Ra Ac Rf Db Sg Bh Hs Mt D

s                

Ce Pr Nd

Pm

Sm Eu Gd T

bDy

Ho Er T

mYb Lu

Th Pa U Np Pu A

mCm

Bk Cf Es F

mMd

No Lr

GROUPS – Similarities: The number of

electrons in the outer shell. Common reactivity, bonding, chemical and physical properties.

H       He

Li Be   B C N O F Ne

Na Mg   Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra Ac Rf Db Sg Bh Hs Mt Ds                

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Metaloids

Alkaline Earths

Alkali Metals

Transition Metals

Non-metals

Weak/Poor Metals

Halogens

Noble Gases

Actinides

Lanthanides

H He

Li Be B C N O F Ne

Na

Mg Al Si P S Cl Ar

K Ca Se Ti V Cr Mn Fe Co Ni C

u Zn Ga Ge As Se

BrKr

Rb Sr Y Zr N

b Mo Tc Ru Rh Pd

Ag

Cd In Sn S

b Te I Xe

Cs Ba La Hf Ta W Re Os Ir Pt Au

Hg Tl Pb Bi P

oA

tR

n

Fr Ra Ac Rf Db Sg Bh Hs Mt D

s                

Ce Pr Nd

Pm

Sm Eu Gd T

bD

yH

o Er Tm

Yb Lu

Th Pa U Np Pu A

mCm

Bk Cf Es F

mM

dN

o Lr

METALIC PROPERTIES Similarities: An elements relative ability to conduct energy in the form of

heat or electricity.

the “stair”

Metals

Non metals

Metaloids

Valence Electrons

The number of electrons in the outer shell of an atom

1

2

2

1 2 3 54 6 7 8

1 2 3 54 6 7 8

2 2 2 2 2 2 2

2 2 2 2 2 2 2 28 8 8 88 8 8 8

Valence Electrons11+

2

 2

2+3

3+4

4+ 53-

 62-

71- 

80

               

                            6    

   2                          

                                 

                               

                           

                           

Periodic LawWhen the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties

Atomic RadiusA measure of the distance from the center of the nucleus to the outer-most electron (Bottom Left, Fr has

the largest Atomic Radius)Atomic Number vs. Atomic Radius

0

50

100

150

200

250

300

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

Atomic Number

Ato

mic

Rad

ius

(pm

)

Series2

ElectronegativityAn atoms ability or affinity to gain another electron. Trend (Top right, excluding the noble gasses, F is

the most electronegative element)

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 10 20 30 40 50 60

Atomic Number

Elec

tron

egat

ivity

Series1

Table of Electronegativities

Ionization EnergyThe energy required to lose the

outer-most electron from an element. (Top right, He has the greatest

ionization energy)Atomic Number vs. Ionization Energy

0

500

1000

1500

2000

2500

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

Atomic Number

Ioni

zatio

n En

ergy

(kJ/

mol

)

Series2

ReactivityAn atoms general ability to undergo a

chemical reaction. The Alkali Metals are the most electronegative

family/group. (Bottom Left, Fr is the most reactive)Highly reactive – readily

participates in chemical reactionsUn-reactive – does not readily participate in chemical reactionshttp://teachertube.com/viewVideo.php?video_id=41344&title=Alkali_Metals___Brainiac

Atomic Radius: A measure of the distance from the center of the nucleus to the outer-most electron Electronegativity: An atoms ability or affinity to gain another electron.Ionization Energy: The energy required to lose the outer-most electron from an element.Reactivity: An atoms general ability to undergo a chemical reaction.

Trends of the Periodic Table

4 major trends: top right or bottom left?

H       He

Li Be   B C N O F Ne

Na Mg   Al Si P S Cl Ar

K Ca Se Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra Ac Rf Db Sg Bh Hs Mt Ds                

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Electronegativity (F) &

Ionization Energy

(He) Atomic Radius (F

r) & Reactiv

ity

(Fr)

Chemical Bonding

•Inter- vs Intra-molecular forces•Ionic vs Covalent

Molecular Interactions

Inter-molecular Forces Interaction between molecules that hold it

together in a network. Intra-molecular Forces Forces that hold groups of atoms together

and make them function as a unit

Intra-molecular Forces: Bonding Forces that hold groups of

atoms together and make them function as a unit.

Ionic bonds – transfer of electronsCovalent bonds – sharing of electrons

Metallic Bonding – sea of electrons

Which elements form which type of bond?

Metal / nonmetal = Ionic NaCl, MgBr2

Nonmetal / nonmetal = covalent CO2, CH4, H2O, NOGroup like metals = metalic Fe, Ti, Mg

Review: Why do atoms bond?

To satisfy the octet rule? Yes, but to be more specific, atoms

share electrons in order to complete their outer electron shell making them more stable as they are then in a lower state of energy.

But how do we know what type of bonding will occur between two atoms?

Metal Metalloids Nonmetals

I II III IV V VI VII VIII

Transition metals

Lewis Dot Diagrams

• Lewis Dot Diagrams are used in both ionic and covalent bonding

Simple Rules for BondingDuet Rule: H and He require 2 electrons for

stabilityOctet Rule: All other elements will have 8 valence

electrons for stabilityIn order to achieve this elements can steal (ionic) or share (covalent) electrons

Ions form when atoms lose or gain electrons.

Atoms with few valence electrons tend to lose them to form cations.

Atoms with many valence electrons tend to gain electrons to form anions

NeNNa F

Na+ N3- F-

O

O2-

Mg

Mg2+

Cations

Anions41

Ionic Bonds

Ionic bonds result from the attractions between positive and negative ions.

Ionic bonding involves 3 aspects:1. loss of an electron(s) by one element, 2. gain of electron(s) by a second element,3. attraction between positive and negative

42

Ionic Bonds

Ionic Bonds Electrons are transferred

Electronegativity differences are

Greater than for covalent The formation of ionic bonds is

always exothermic!

A covalent/molecular bond is a chemical bond in which two or more electrons are shared by two atoms.Why should two atoms share electrons?

F F+

7e- 7e-

F F

8e-8e-

F F

F F

Lewis structure of F2

lone pairslone pairs

lone pairslone pairs

single covalent bond

single covalent bond

Covalent Bonds

8e-

H HO+ + OH H O HHor

2e- 2e-Lewis structure of water

Double bond – two atoms share two pairs of electrons

single covalent bonds

O C O or O C O

8e- 8e-8e-double bonds double bonds

Triple bond – two atoms share three pairs of electronsN N8e-8e-

N N

triple bondtriple bondor

Covalent Bonds

Linear

180o

Covalent Bonds

Trigonal Planar

120o

Covalent Bonds

Tetrahedral

109.5o

Covalent Bonds

Pyramidal (Tetrahedral)

107o

Covalent Bonds

Bent (Tetrahedral)

104.5o

Covalent Bonds

Boron Trifluoride Non-Polar (even)

F

B

F F

Trigonal planar shape: BF3 violates the octet rule

Covalent Bonds

..H N H

H

Ammonia NH3 – Polar (uneven)

Covalent Bonds

Trigonal Bipyramidal / Octahedral

120o

90o 90o

90o

Covalent Bonds

Explain intra/inter molecular bonding, the difference between covalent/ionic bonds, how you determine bonding type, and types of bonds:

Review……Covalent Bonds

Chemical Reactions & Nomenclature•Nomenclature for

• Ionic, covalent, acids•Types of Chemical Reactions•Balancing

Look at the First Element!!A metal = MUST BE IONIC Does it have a polyatomic? Does it have a transition metal?A nonmetal = MUST BE COVALENTHydrogen = MUST BE AN ACID Binary Acid? Oxoacid (Polyatomic)?

first element Metal = IonicNO prefixesThe simplest whole number ratio is generally the ionic formula. (empirical formula)

BinaryNaClMgBr2

Li2S

Polyatomic

Na2CO3

Mg(NO3)2

Li3PO4

TransitionFeCl3

Ni3(PO3)2

ZrSO4

Polyatomic Ions(Common 11)

PO43- PO3

3- OH-

NO2- NO3

- NH4+

SO32- SO4

2- CO32-

ClO3- ClO2

-

First element nonmetal = Covalent

Greek Prefixes Mono (1), di (2), tri (3), tetra (4), penta (5),

etc…. First nonmetal keeps element name Change ending of second nonmetal to –ide

P2O5 CCl4 CO2 COSiO2

NO2 CF4 SF6 PF5NO

First element hydrogen = Acid

BinaryH and another

elementUse hydro- prefix

Use –ic suffixHCl HFHBrH2S HI

Oxoacid / PolyH and 2 or more

NO prefixIf poly –ate -ic If poly –ite -ous

HNO3 H3PO4

H3PO3 H2SO4

Reaction TypesSynthesis/Composition (A + B AB)Decomposition (AB A + B)Single Replacement (A + BC B + AC)Double Replacement (AB + CD CB + AD)Combustion (CxHy + O2 CO2

+ H2O)

Balancing EquationsConservation of MassThere must be the same amounts of each element on each side

__ C3H8 + ___ O2 ___ CO2 + ___ H2O___ KClO3 ___ KCl + ___ O2

__ N2O3 + __ H2O __ HNO2