Element - GCSE Chemistry Definition

What is an element?

In GCSE chemistry, an element is a substance made up from one type of atom. They cannot be broken down into anything simpler. Each element is represented by its own unique chemical symbol, which can be seen on the Periodic Table.  

All atoms of the same element will contain the same number of protons. For example, carbon atoms all have 6 protons. Elements also exist as either single atoms or molecules. Molecules are a group of two or more atoms which are chemically combined. For instance, carbon exists as carbon atoms, but nitrogen will exist as nitrogen molecules. Nitrogen molecules have the formula N₂, with the two nitrogen atoms chemically combined. 

Elements are represented using their chemical symbol, some consisting of one letter, and others of two. Where a symbol contains 2 letters, the first one is always written in uppercase and the other in lower case e.g. Mg not MG. It is important that there is a distinction in the height of your letters when writing chemical symbols, particularly in equations. In exams, if the lowercase letter is a similar height to the uppercase letter, you may lose marks.

Elements are grouped together in the Periodic Table based on their chemical properties. For GCSE chemistry, you generally need to be able to describe the properties of Group 1 (the alkali metals), Group 7 (the halogens), Group 0 (the noble gases) and transition metals.