GCSE Core Chemistry Exam tip; A symbol represents 1 atom of an element. Key words; Atom, Compound,...

GCSE Core Chemistry

Exam tip; A symbol represents 1 atom of an element.

Key words; Atom, Compound, Electron, Element, Symbol

GCSE Core Chemistry


Learning Objectives

By the end of the lesson I can:

•Recall that all substances are made up of atoms

•Describe and explain what is inside an atom

•Describe how elements contain only one type of atom

•Understand that symbols are used for atoms to show what happens in chemical reactions.

•Know that all 100 known elements are listed on the periodic table and groups have similar properties

GCSE Core Chemistry


atom – The smallest particle that can exist on its own.

compound – Substance made up of two or more different elements that are chemically joined together.

element – Substance made up of only one type of atom.

GCSE Core Chemistry


Atoms – the building blocksAll substances are made from very tiny particles called atoms.

John Dalton had ideas about the existence of atoms about 200 years ago but only relatively recently have special microscopes (called electron microscopes) been invented that can ‘see’ atoms.

The yellow blobs in this image are individual gold atoms, as seen through an electron microscope.

GCSE Core Chemistry


Daltons Atomic Theory• All matter is made up of tiny particles called atoms.

• Atoms cannot be created or destroyed (as stated in the Law of Conservation of matter)

• All atoms of an element are THE SAME

• Atoms of one element are completely different to the atoms of another element

• Atoms combine in small numbers to form molecules

Devise the Devise the

LAW OF LAW OF CONSERVATION OF CONSERVATION OF

MASSMASS

(2 mins)(2 mins)

GCSE Core Chemistry


Even smaller particles

proton

neutron

electron

Scientists now know that atoms are actually made from three even smaller particles:

These particles are so small weighing them in grams is meaningless

So instead we say Protons and Neutrons have a mass of one unit, whereas, electrons are smaller, about 1/2000 of a unit (effectively nothing)

Some particles have an electrical charge

GCSE Core Chemistry


Whilst this is still not completely accurate, this is how we draw an atom when we are learning science at secondary school

Draw an Draw an atom and try atom and try

to label it to label it with the 3 with the 3 sub atomic sub atomic

componentscomponents

GCSE Core Chemistry


This is a bit more accurate because we have no idea of where the electrons are at any one time – they are in a cloud called the electron cloud.

GCSE Core Chemistry


Inside an atom

Atoms always have the same number of protons and electrons, making them neutral

1.1. Draw an atom and annotate itDraw an atom and annotate it2.2. Use a ‘METAPHOR’ Use a ‘METAPHOR’

to explain the atom conceptto explain the atom conceptto a 10 year old child (year 6) to a 10 year old child (year 6)

GCSE Core Chemistry


Imagine a hoola hoop

Now imagine a ball somewhere in the middle of the hoop. This represents the nucleus

Now imagine a car running round the outside somewhere. This represents an electrons

GCSE Core Chemistry


What is left is a very simple and not completely accurate model of an atom

GCSE Core Chemistry


Include annotated detail

1

11/2000

+1

-10

GCSE Core Chemistry


ElementsElements• There are about 100 different elements listed on the periodic

table of elements• Elements are made up of just one type of atom.• Each atom in an element has the same number of protons.• Different elements have different numbers of protons in

their atoms. • The atomic number of an element is its number of protons.• The mass number of an element is its number of protons and

neutrons• There is an equal number of protons and electrons

How can you find How can you find the number the number of neutrons?of neutrons?

How can you find How can you find the number the number

of ELECTRONS?of ELECTRONS?

GCSE Core Chemistry


Symbols

• Every element has a symbol as a shorthand way of writing it down.

• Symbols have one or two letters.

• The first letter is always a capital letter. The second is always lower case.

O Na

Cl K

GCSE Core Chemistry


1. Board game: carbon, helium, two sulphurs

2. Relative: sulphur, oxygen, nitrogen 3. Fuel: carbon, oxygen, aluminium

4. Group of fish: sulphur, hydrogen, oxygen, aluminium

5. For the rubbish: boron, iodine, nitrogen

CHeSS

SON

COAl

SHOAl

BIN

Write down the symbols for each element listed and use these to spell out a word that matches the clue.

GCSE Core Chemistry


In some elements, the atoms are joined in groups of two or more. A particle containing atoms grouped in this way is called a molecule.

An element is a substance made up of only one type of atom.

Other elements, that contain atoms joined in molecules are hydrogen, nitrogen, chlorine and bromine.

Oxygen is an element made up of oxygen

atoms only.

How many atoms are there in an oxygen

molecule?

GCSE Core Chemistry


In some elements, the atoms are joined together and form molecules. Combining the symbols of the atoms in a molecule gives you the formula of the molecule.

What is the formula for the molecules in each element?

nitrogen

oxygen

N2

O2There are groups of

two atoms in each

molecule.

GCSE Core Chemistry


CREATING ELEMENTAL POETRYCREATING ELEMENTAL POETRY

The originalThe originalhttp://www.youtube.com/watch?v=GFIvXVMbII0The rapThe raphttp://www.youtube.com/watch?v=pmTXtbRR7c0

&feature=relatedEveryone can do it!!!Everyone can do it!!!http://www.youtube.com/watch?v=QWkVO6Bp8VM

&feature=related

GCSE Core Chemistry


CREATING ELEMENTAL POETRY

Use what you’ve heard and the periodic table and textbooks to write a poem/song about

EITHER1. an element and its properties OR2. a number of elements on the periodic

table

GCSE Core Chemistry


Learning Objectives

By the end of the lesson I can:

•Recall that all substances are made up of atoms

•Describe and explain what is inside an atom

•Describe how elements contain only one type of atom

•Understand that symbols are used for atoms to show what happens in chemical reactions.

•Know that all 100 known elements are listed on the periodic table and groups have similar properties

GCSE Core Chemistry


Atoms and symbols

All substances are made up of p______. The smallest p_____ that can take part in a chemical reaction is called an a___.

Elements are substances that each contain only _______ of atom. The atoms of each element are represented by a symbol.

Examples of symbols used for elements are O (used for ______), N (used for _______) and Cu (used for ______).

articlesarticle

tom

one type

oxygen nitrogencopper

GCSE Core Chemistry


More work on symbolsFill in the gaps in the table below.

Sodium

Bromine

Ag

C

Chlorine

SymbolName of element

Cl

Carbon

Silver

Br

Na

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How are the elements arranged?Answer: Using the Periodic Table

Vertical columns are called

___________ and

horizontal rows are called

___________.

groups

periods

GCSE Core Chemistry


Elements, mixtures and compounds

Elements – these are substances containing only ______________. For example, sodium is an element and is made up of sodium atoms only.

Compounds – these are substances made up of two or more types of atom. These atoms are joined together chemically. For example, carbon dioxide contains carbon and oxygen atoms joined together by chemical bonds.

one type of atom

GCSE Core Chemistry


Mixtures – these are not pure substances. The compounds and/or elements making them up are not joined chemically. For example, air is a mixture of gases like oxygen (an element) and carbon dioxide (a compound).

GCSE Core Chemistry


Elements, mixtures and compounds, continued

Classify the following substances as elements, mixtures or compounds.

mixture compound element

GCSE Core Chemistry


How do we name compounds?The rules are:

1. If there are two elements present, then the name ends in –IDE.

For example, the formula CuS represents the compound _________ide.

2. If there are three elements present and the third one is oxygen, then the name ends in –ATE.

For example, the formula CuSO4 represents _________ate.

copper sulf

coppersulf

GCSE Core Chemistry


Naming compounds, continuedName the compounds in the table below.

Formula Name

AlCl3

CuO

Fe2O3

CaSO4

CaCO3

MgBr2

NaNO3

Aluminium chloride

Copper oxide

Iron oxide

Calcium sulfate

Calcium carbonate

Magnesium bromide

Sodium nitrate

GCSE Core Chemistry


Chemical reactions

The substances that react are called the

REACTANTS.The substances formed are called the

PRODUCTS.

To represent chemical reactions we write word equations or symbol equations.

REACTANTS PRODUCTS

GCSE Core Chemistry


Chemical reactions, continuedWrite word equations for the following reactions

1 When sodium is burned in oxygen, sodium oxide is formed.

sodium(s) + oxygen(g) sodium oxide(s)

2 When solid calcium carbonate is heated, it decomposes into solid calcium oxide and carbon dioxide gas.

Calcium carbonate(s)calcium oxide(s)

heat carbon dioxide(g)+

GCSE Core Chemistry


Does the mass change during a chemical reaction?

The answer to this is ___.NO

For example, when 56 g of iron reacts with 32 g of sulfur iron sulfide is formed. The mass of the iron sulfide formed is __ g.88

When 48 g of magnesium is heated in oxygen, 80 g of magnesium oxide is formed. What mass of oxygen is needed to react with the magnesium?

The answer is __ g. 32

GCSE Core Chemistry


Burning fossil fuels

The three fossil fuels are:Coal, oil and natural gas.

When the fossil fuels are burned in enough air they always form water and carbon dioxide. Carbon dioxide is a __________ gas and is linked to g____ w______.

greenhouse lobalarming

Write the word equation for methane (natural gas) burning in oxygen.

methane(g) + oxygen(g) carbon dioxide(g) + water(l)

GCSE Core Chemistry


The Reactivity Series

Metals are arranged in order of how reactive they are. A more reactive metal will displace a less reactive one from its compounds.

For example, zinc will displace copper from copper sulfate to give zinc sulfate plus copper. The word equation is:

zinc(s) + copper sulfate(aq) zinc sulfate(aq) + copper

GCSE Core Chemistry Exam tip; A symbol represents 1 atom of an element. Key words; Atom, Compound,...

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