The term Trivalent is used to describe any atom that can form 3 bonds i.e. it has a valency of +3 or -3.
- Trivalent elements like nitrogen and phosphorous that have a valency of -3.
A quick cheat is to look at the periodic table to identify the valency. All elements in group 3 have a valency of +3 while all elements in group 5 have a valency of -3.
- We can also have monovalent functional groups. Examples include the carboxyl group (−COOH), the phosphino group (R3P).