Question

What is the name of a binary compound made up of $MgC{l_2}$?

Answer 1

An ionic compound which consists of only two elements, one is present as a cation while other is present as an anion, is called a binary ionic compound. For naming binary ionic compounds, first identify the cation and anion in the given compound and then name of cation precedes the name of anion while naming the compound.

Complete answer:
We know that an ionic compound is a chemical compound in which two oppositely charged ions are held together by ionic bonds. Generally, the positively charged species consist of metal cations while the negatively charged species consist of monovalent or polyatomic anions.
An ionic compound is always named first by its cation and then by its anion. The name of the cation is the same as that of its element. For example, if we consider ${K^ + }$, then it is called potassium ion (same as the name of the element i.e., potassium). While naming the anionic part of the compound, the root name of the anion is written along with the suffix “ide”. For example, if we consider ${F^ - }$, then it will be written as fluoride.
Thus, for the given compound, the cation is $M{g^{2 + }}$ and the anion is $C{l^ - }$ and as two chlorine atoms exactly balance the charge of magnesium ion, so the overall compound is electrically neutral. Hence, the name of the given binary compound i.e., $MgC{l_2}$ is magnesium chloride.

Note:
It is important to note that if either of the ion in the compound is polyatomic ion i.e., it consists of more than one element in its cationic or anionic part., then the name of polyatomic ion is used in the name of overall compound remains the same i.e., no suffix is added. For example, in $Ca{(N{O_3})_2}$, cation is $C{a^{2 + }}$ which will be named as calcium and the anion is $NO_3^ -$ which is a polyatomic ion and its name is nitrate ion. So, the overall name of the compound is calcium nitrate.