Ions of Elements


Ions are atoms or groups of atoms that have either lost or gained electrons so they have a positive or negative charge.

Ions are different to isotopes and are not to be confused. Ions are atoms that have gained or lost electrons. Electrons as a particle can be easily removed and added to an atom, unlike protons neutrons and electrons. This leads to the formation of ions. Negative ions called cations form as if an atom gains electrons it now has more electron than protons that means there is not a balanced number of protons and electrons. Where as if an atom loses electrons it becomes a positive ion called an anion it now has fewer electrons than protons meaning it has a positive charge. Atoms do this so they can have a full outer shell of electrons and be more stable in energy.

If we look at two examples. Lithium is a metal that loses an outer electron and as a result will become positively charged. This is because by losing electrons it now has 2 electrons in its outer shell and 3 protons in its nucleus. Meaning there are more positive sub atomic particles than negative creating a positive charge.

On the other hand if we look at oxygen, the oxygen atom has 6 electrons in its outer shell but instead of losing 6 electrons it is easier for oxygen to gain 2 electrons and becoming a charge of -2 on the ion. This is because the oxygen ion has 8 protons but 10 electrons so it has more electrons meaning it will have a -2 charge.

Terms in section

A proton is a positive particle that makes up the atom in the nucleus with a positive charge


A neutron is a neutral sub atomic particle that makes up the nucleus with the proton


An ion forms when an atom loses or gains electrons to form a positive or negative particles due to the unbalanced number of protons


Isotopes are atoms of the same element with different number of neutrons and the same number of protons. React chemically the same but have a different masses


The electron is the smallest sub atomic particle that make up the atom. Has a negative charge and is located in shells that orbit the nucleus


A cation is a positively charged ion


An anion is a negatively charged particle

Sub atomic

Sub atomic is a term used to describe parts of the atom that are the smaller than the atom itself, the proton neutron and electron


The nucleus is the term given to the centre of the atom comprising of the proton and neutron


Isotopes of Elements


Why is the Periodic Table so Important?