What element on the periodic table has a period of 3, and a group of 5?

The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon. The first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the p-block.

In the 3rd period there are 8 elements.