1. What should we already know?
We are going to go over topics that we covered at Key Stage 3 and need to know for the next few topics.

2. 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 ______).
articles
article
tom
one type
oxygen
nitrogen
copper
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3. More work on symbols Fill in the gaps in the table below.
Name of element
Symbol
Chlorine Cl
Carbon C
Silver Ag
Bromine Br
Sodium Na
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4. How are the elements arranged?
Answer: Using the Periodic Table
Vertical columns are called
___________ and
horizontal rows are called
___________.
groups
periods
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5. 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
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6. Mixtures – these are not pure substances
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).
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7. Elements, mixtures and compounds, continued
Classify the following substances as elements, mixtures or compounds.
mixture
compound
element
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8. How do we name compounds?
The rules are:
If there are two elements present, then the name ends in –IDE.
For example, the formula CuS represents the compound _________ide.
If there are three elements present and the third one is oxygen, then the name ends in –ATE.
For example, the formula CuSO represents _________ate.
copper
sulf
copper
sulf
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9. Naming compounds, continued
Name 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
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10. Chemical reactions The substances that react are called the
REACTANTS.
The substances formed are called the
PRODUCTS.
REACTANTS
PRODUCTS
To represent chemical reactions we write word equations or symbol equations.
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11. Chemical reactions, continued
Write 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 oxide(s)
carbon dioxide(g) +
heat
Calcium carbonate
(s)
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12. 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
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13. 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
lobal
arming
Write the word equation for methane (natural gas) burning in oxygen.
methane(g) + oxygen(g) carbon dioxide(g) + water(l)
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14. 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
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