Elements: The Building Blocks of Everything

Every material you have ever touched is built from a surprisingly small set of pure substances called elements.

An element is a pure substance that cannot be broken down into any simpler substance by ordinary chemical means. About 118 elements are known, and roughly 90 of those occur naturally on Earth.

Each element has a name and a symbol. The rule for symbols is strict:

• one capital letter (O oxygen, C carbon, N nitrogen, H hydrogen); or
• a capital letter followed by a small letter (Fe iron, Cu copper, Al aluminium, Pt platinum, Mn manganese, Ca calcium).

Some symbols look nothing like the English name because they come from Latin: Fe from ferrum (iron), Cu from cuprum (copper), Au from aurum (gold), Ag from argentum (silver), Na from natrium (sodium). These are worth knowing, because South Africa mines several of them.

Worked example — reading a list of symbols. A learner writes: Na, Cl, Na, O, Cl, H.

How many different elements appear? Strike out the repeats: Na, Cl, Na, O, Cl, H → Na, Cl, O, H = 4 different elements, even though six symbols were written.

Elements join together in different combinations to make everything around us — sea water, rock, wood, your own body. Exactly how they join is the story of Grade 9; for now, the important idea is that a short list of elements is enough to build the whole world.