Question

What is the name of Cu $_{3}$ P?

Answer 1

In this question what we know is Cu $_{3}$ P is an ionic compound, so what we have to do is to first recognize the cation and anion and after that we can write name as in order of cation first then name of anion.

Complete step by step answer:
Before coming to the solution first we understand some basic terms like:
Cation: A cation is positively charged ion with majority number of protons than electrons. For example: all metals are cations.
Anion: An anion is negatively charged ion with a majority number of electrons than protons. For example: all non-metals are anions.
For naming we have to first identify the cation and anion in the compound which is Cu(copper) and P(phosphorus) respectively.
The charge on the metal (which is $+1$ in our case) is written in roman numerals and is placed inside the parentheses to indicate that the element is a transition metal (element that are partially filled d orbitals). Transition metal can assume more than one charge, so it’s just easier to be more specific when stating the charge of a transition metal.so name becomes copper ( $i)$ .
Now the anion (non-metal) is phosphorus, but we have to take the root word and change its ending with -ide. And so, the phosphorus becomes phosphide.
Now write the name of cation and anion together i.e., copper $(i)$ phosphide.

Note:
Always try to write the name of the first element (roman numeral of charge in parentheses if dealing with transition metal) $+$ root name of second element i.e., the suffix -ide.