What types of compounds use prefixes in the names?

Prefixes are used in the names of covalent compounds, which are compounds formed by the sharing of electrons between nonmetal atoms.

Here's why prefixes are important for covalent compounds:

* Variable bonding: Unlike ionic compounds where metals and nonmetals have fixed charges, nonmetals can form multiple bonds with each other. This means a single pair of elements can form different compounds with varying ratios.

* Clarity: Prefixes provide a clear indication of the number of each atom present in a molecule.

Examples:

* CO - Carbon monoxide

* CO2 - Carbon dioxide

* N2O - Dinitrogen monoxide

* PCl5 - Phosphorus pentachloride

Prefixes commonly used:

* Mono- (1)

* Di- (2)

* Tri- (3)

* Tetra- (4)

* Penta- (5)

* Hexa- (6)

* Hepta- (7)

* Octa- (8)

* Nona- (9)

* Deca- (10)

Important Note: The prefix "mono-" is often omitted for the first element in a covalent compound, unless there are multiple possibilities.