The protons and neutrons are found in the nucleus at the centre of the atom. The nucleus is very much smaller than the atom as a whole. The electrons are arranged in shells around the nucleus.
|Particle||Relative mass||Relative charge|
|Electron||This can be described as negligible (almost zero).||–1|
The number of electrons in an atom is always the same as the number of protons, so atoms are electrically neutral overall.
Atoms can lose or gain electrons. When they do, they form charged particles called ions: