What is the chemical name of the compound NH4SCN?
(1) ammonium thiocyanate
(2) ammonium cyanide (3) nitrogen hydrogen cyanide
(4) nitrogen hydrogen sulfate
Explanation: In order to name a compound, we must first figure out whether it is ionic or covalent.
Ionic compounds can be divided into tfour categories: metal + nonmetal, metal+ polyatomic ion, polyatomic ion+ polyatomic ion, polyatomic ion + nonmetal. Covalent compounds consist of 2 nonmetals (nonmetals are found to the right of the staircase on the Periodic Table).
What is a polyatomic ion? It is an ion (charged atom) consisting of 2 or more elements. The Reference Table has Table E, Selected Polyatomic ions. If we look at Table E, we can see that NH4+ is a polyatomic ion and so is SCN-. Since the compound consists of two polyatomic ions, it is indeed an ionic compound. To name an ionic compound consisting of two polyatomic ions, we simply name the first polyatomic ion followed by the name of the second polyatomic ion. We can find polyatomic ion names in Table E. Therefore, the name for NH4SCN is (1) ammonium thiocyanate.
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