An ion is an electrically charged atom or group of atoms formed by the loss or gain of electrons

• This loss or gain of electrons takes place to obtain a full outer shell of electrons

• The electronic structure of ions of elements in Groups 1, 2, 6 and 7 will be the same as that of a noble gas - such as helium, neon, and argon

• Negative ions are called anions and form when atoms gain electrons, meaning they have more electrons than protons

• Positive ions are called cations and form when atoms lose electrons, meaning they have more protons than electrons

• All metals lose electrons to other atoms to become positively charged ions

• All non-metals gain electrons from other atoms to become negatively charged ions

When atoms lose there electron they become electro positive

When atoms gain electrons or lose protons they become electronegative