Chemical reactions can be described with word equations. These equations show how the atoms rearrange themselves during the reaction. The first thing you need to understand is the names of the chemicals because this tells you which elements you are dealing with. You will probably only be asked about chemicals containing the following elements.
| Symbol | Name |
Metal or Non-Metal |
State at R.T.P.1 |
Interesting factoids… |
| Al |
Aluminium |
Metal |
Solid |
Low density and highly abundant, used for foil and drinks cans |
| Ar | Argon |
Non-Metal |
Gas |
1% of air, totally unreactive, noble gas |
| Br | Bromine |
Non-Metal |
Liquid |
Brown, smelly and reactive |
| Ca | Calcium |
Metal |
Solid |
Reactive metal found in limestone, limewater, teeth & bones |
| C | Carbon |
Non-Metal |
Solid |
Conducts electricity, the basis of all living things, forms long chains |
| Cl | Chlorine |
Non-Metal |
Gas |
Green, toxic, highly reactive gas |
| Cu | Copper |
Metal |
Solid |
Pinkish brown, excellent conductor of heat and electricity |
| F | Fluorine |
Non-Metal |
Gas |
Reacts to form fluoride which helps protect teeth from decay |
| Au | Gold |
Metal |
Solid |
Very unreactive, rare, dense metal |
| He | Helium |
Non-Metal |
Gas |
Unreactive gas with a very low density |
| H | Hydrogen |
Non-Metal |
Gas |
Explosive, found in water & acids, the smallest/lightest element |
| I | Iodine |
Non-Metal |
Solid |
Forms a blue/black colour with starch |
| Fe | Iron |
Metal |
Solid |
Strong, cheap, magnetic metal that rusts if oxygen & water are present |
| Pb | Lead |
Metal |
Solid |
Poisonous, dense, soft metal |
| Mg | Magnesium |
Metal |
Solid |
Burns in air with a bright flame |
| Mn | Manganese |
Metal |
Solid |
Part of potassium permanganate |
| Hg | Mercury |
Metal |
Liquid |
Dense, highly toxic, unreactive |
| Ne | Neon |
Non-Metal |
Gas |
A noble gas |
| N | Nitrogen |
Non-Metal |
Gas |
78% of the air, unreactive, found in protein |
| O | Oxygen |
Non-Metal |
Gas |
The thing with which things react when they burn in air |
| P | Phosphorus |
Non-Metal |
Solid |
An important plant mineral |
| K | Potassium |
Metal |
Solid |
A highly reactive metal |
| Si | Silicon |
Non-Metal |
Solid |
Used to make diodes, transistors and computer chips |
| Ag | Silver |
Metal |
Solid |
Excellent conductor, very unreactive |
| Na | Sodium |
Metal |
Solid |
Highly reactive, with chlorine forms table salt |
| S | Sulphur |
Non-Metal |
Solid |
Yellow, reactive, forms sulphur dioxide when burnt (acid rain) |
| Sn | Tin |
Metal |
Solid |
Unreactive, shiny, soft metal |
| Zn | Zinc |
Metal |
Solid |
Reacts with cold acid but resists water (galvanising) |
1Room temperature and pressure
Some of those elements combine to form compounds. The compound’s name tells you what elements it contains. For example, if a compound name ends in –ide then this shows that just that single element is attached. For example…
|
Element One |
Element Two |
Compound | ||
|
copper |
+ |
oxygen |
→ |
copper oxide |
|
iron |
+ |
sulphur |
→ |
iron sulphide |
|
sodium |
+ |
chlorine |
→ |
sodium chloride |
|
aluminium |
+ |
iodine |
→ |
aluminium iodide |
|
zinc |
+ |
bromine |
→ |
zinc bromide |
|
sulphur |
+ |
oxygen |
→ |
sulphur dioxide |
Some compounds have more complicated names and may contain more than two elements; however the name still tells us what it contains. The ending –ate indicates that the compound contains oxygen. For example…
| Compound | Contains |
| Copper sulphate | copper, sulphur, oxygen |
| Zinc carbonate | zinc, carbon, oxygen |
| Potassium permanganate | potassium, manganese, oxygen |
There are some other names you should know. Hydroxide means an oxygen atom and a hydrogen atom (OH), bicarbonate means with an extra hydrogen atom, monoxide means “with one oxygen atom attached”, dioxide means “with two oxygen atoms attached” and trioxide means “with three oxygen atoms attached”. For example…
| Compound | Contains |
| Calcium hydroxide | calcium, hydrogen, oxygen |
| Sodium hydroxide | sodium, hydrogen, oxygen |
| Carbon monoxide | carbon, oxygen (CO) |
| Nitrogen trioxide | nitrogen, oxygen (NO3) |
| Sodium bicarbonate | sodium, hydrogen, carbon, oxygen |
Acids tend to have abbreviated names but it may help to know their proper names too.
| Acid | Chemical Name |
Chemical Formula |
Salt Formed |
| sulphuric acid | hydrogen sulphate |
H2SO4 |
sulphate |
| hydrochloric acid | hydrogen chloride |
HCl |
chloride |
| nitric acid | hydrogen nitrate |
HNO3 |
nitrate |
When compounds react with one another, exactly the same number and type of element is present at the beginning as at the end of the reaction. This is called the “conservation of matter” and is a basic Law of the Universe. Even though the elements have rearranged themselves, there must be the same ones present after the reaction as were present before. I will write more about this in my next post.
Questions…
- Name a non-metal element which is a solid at room temperature.
- Name a metal element that is a liquid at room temperature.
- What compound forms when potassium and iodine react?
- What elements would you find in a molecule of sodium chlorate?
- What might the chemical name of citric acid be?
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