Ionic Bonding

Spec 1.27 describe the formation of ions by the gain or loss of electrons

We think of atoms 'losing' an electron to another, what is really happening is that one of the atoms is attracted to the electron pair much more strongly than the other one. The electron pair is then pulled very close to that atom and away from the other one. Hence this atom gains an electron, whilst the other loses one.

[Note in a covalent bond, the electrons are shared between two atoms. Both nuclei are attracted to the same electron pair.]

The electrically charged particles are called ions. An ion is an atom which carries an electrical charge, either positive or negative.

• a positive ion is called a cation
• a negative ion is called an anion [tip: anion= A-Negative-ION]

Ionic bonding is bonding in which there has been a transfer of electrons from one atom to another to produce ions. The substance is held together by strong electrostatic attraction between the positive and negative ions.