Question

When naming a transition metal ion that can have more than one common ionic charge, the numberical value of the charge can be indicated by a ____
(A) prefix.
(B) suffix.
(C) Roman numeral following the name.
(D) superscript after the name.

Answer 1

Answer: C) Roman numeral following the name.

Explanation: If we want to name an ionic compound like NaCl then we can easily write its name. Na is sodium and Cl is chlorine. First we write the name of the metal ion and then the name of the anion it has. Here we have mono atomic ion and for these we use the suffix -ide. So, the name will be sodium chloride.

Now, if we have something like $FeCl_3$ and we write the name as Iron chloride, then it will not be correct since Fe is a transition metal and it shows +2 and +3 oxidation states. So, to overcome this difficulty, a roman numeral is used for the oxidation state of the metal ion. The name of above compound will be Iron(III)chloride. Similarly, if we have $FeCl_2$ then its name will be written as Iron(II)chloride.

In both the above names, the roman numerals (III) and (II) are indicating numerical value of the charge of the metal ion. So, the correct choice is C) Roman numerals following the name.

when naming a transition metal ion that can have more than one common ionic charge, the numerical value of the charge can be indicated by a Roman numeral following the name.