Hello,

The third period elements (Na, Mg, Si, PS, Cl, Al) are called Typical Elements. They are called so because they represent properties of their own group.

Do not confuse this term with bridge elements, because concepts are totally different. Bridge elements are those elements which show diagnol relationship, found in period 2 and period 3.

Typical elements are also called Representative elements.

Hope it helps.

Good Luck!