The term Tetravalent is used to describe any atom that can form 4 bonds i.e. it has a valency of +4 or -4.
- Tetravalent elements like carbon and chlorine that have a valency of -4 and +4 respectively. (In actuality, carbon can have a valency of both +4 or -4. But since it requires a lot of energy to remove 4 electrons, the carbon atom prefers to gain the 4 electrons by sharing electrons with the atom it is bonded to. Also, remember, the 4 bonds of carbon come in the form of sp3-hybridised orbitals)
A quick cheat is to look at the periodic table to identify the valency. All elements in group 4 have a valency of either +4 or -4