Question

What is the IUPAC name of the following compound $FeS$ ?

Answer 1

Hint :We know that the IUPAC devised a set of instructions or rules that helped in naming the organic molecules. This helped scientists to derive names of the molecules which were not even discovered. These rules have been revised from time to time to improve the quality of nomenclature.

Complete Step By Step Answer:
The IUPAC stands for International Union of Pure and Applied Chemistry. It has formulated some rules for the systematic nomenclature of organic compounds which are even revised later on for the uniform naming of compounds. The IUPAC has laid down some rules which govern the naming of all the organic compounds. This is necessary so that there is uniform nomenclature to be followed world-wide. The IUPAC name of any molecule consists of three parts; Prefix, stem name and suffix.
The first thing to recognize here is that you're dealing with an ionic compound made up of iron, $Fe,$ a metal, and sulfur, $S,$ a nonmetal. Right from the start, you should know that the metal will form a positively charged ion, i.e. a cation, and the nonmetal will form a negatively charged ion, i.e. an anion. Now, grab a periodic table and look for sulfur. You'll find it located in period three, group $16.$ For main group elements, the group number gives you the number of valence electrons.
In this case, sulfur has six valence electrons, which means that it needs two more electrons to complete its octet. You can thus say that sulfur will take these two electrons from iron and form $2-$ anions. Keep in mind that anions are always named using the -ide suffix. In this case, the sulfur ion is called the sulfide anion, $S^{2-}$ .If you take $x+$ to be the charge on the iron cation,
This is important because iron is a transition metal, which means that it can form multiple cations. To distinguish between the possible charges on the iron cation, you must use Roman numerals. In this case, the iron cation has a $2+$ charge, which means that you'll use the (II) Roman numeral. The name of the compound will thus be $FeS\to iron(II)sulfide.$
Therefore, the IUPAC name of the following compound $FeS$ is $Iron(II)sulfide.$

Note :
The IUPAC nomenclature is needed because earlier every chemist gave its own new name to the molecule it discovered. As a result, one molecule had different names. It was difficult to study them. No one got to know whether the molecule discovered by him/her is the new one or the one that has already been discovered. So, the scientist devised some formulations to uniform the naming of compounds.