Formation of Ions

Ions

Charged particles

Ions are formed when atoms gain or lose electrons

They do this to get a full outer shell e.g a noble gas

This is because a full outer shell is very stable

Metal atoms

LOSE electrons from outer shell to form POSITIVE IONS.

Non-metal atoms

GAIN electrons from outer shell to form NEGATIVE IONS

The number of electrons lost or gained is the same as the charge on the ion

If 2 electrons are lost, the particle now has 2 more protons than electrons

Charge = 2+

If 3 electrons are gained, the particle now has 3 more electrons than protons.

Charge = 3-

GROUP 1 and 2 elements are metals.

They LOSE electrons to form POSITIVE IONS

GROUP 6 and 7 elements are non-metals.

They GAIN electrons to form NEGATIVE IONS

Elements in the same group all have the same number of outer electrons.

So they will need to lose or gain the same amount

So they can form with atoms that have the same charge

Group 1 elements form ions by losing one electron (1+ charge)

Group 2 elements form ions by losing two electrons (2+ charge)

Group 6 elements form ions by gaining two electrons (2- charge)

Group 7 elements form ions by gaining one electron (1- charge)

GROUP 1 and GROUP 7 elements can bond since they have the same charge where GROUP 1 elements need to lose an electron and GROUP 7 elements need to gain one

GROUP 2 and GROUP 6 elements can bond since they have the same charge where GROUP 2 elements need to lose two electrons and GROUP 6 elements need to gain two.