How to use the symbols

• Each element has a unique symbol, usually one or two letters

• The first letter of an element's symbol is always capitalized, and if there is a second letter, it is lowercase

• For example, the symbol for hydrogen is 'H', and the symbol for helium is 'He'

Na that doesn't make sense

Sometimes, an element's symbol doesn't match its English name because it's based on its name in another language, like 'Na' for sodium, which comes from the Latin word 'natrium'

What about the little numbers?

When we see small numbers written below and to the right of an element's symbol, called subscripts, they show how many atoms of that element are in a molecule, like the '2' in H₂O meaning there are two hydrogen atoms.

The small numbers beside an element's symbol, show how many atoms of that element are in a molecule, like the '2' in H₂O for two hydrogen atoms.

Why NaCl and not ClNa?

Elements are written in a specific order, usually starting with the element that is most to the left on the periodic table, or if the compound contains carbon, it is usually written first, followed by hydrogen.

In a chemical formula, elements are written in a set order, usually starting with the leftmost element on the periodic table, with carbon and hydrogen often listed first.

Please go to the all year 8 stile page and complete the task called "week 5 - elements and compounds"