Question

When naming chemical elements, how do I know when to use the prefixes (mono-,di-,tri-, etc.) or the roman numerals in paranthesis? I noticed I am getting some wrong. Sometimes I don't need the prefixes at all or sometimes I need the parenthesis instead of the prefixes or vice versa. I know there are different compounds when it comes to naming such as binary compounds, polyatomics, transition metals, etc. I need some clarification on the topic.

For example, GaBr3 is Gallium(III) Bromide but GaCl3 is Galium Trichloride.

Answer 1