Question

What is the rule for accounting for transition metals in naming ionic compounds?
A. Add a Roman numeral in parentheses after the cation to denote the charge on cation.
B. Add a Roman numeral in parentheses after the anion to denote the charge on cation.
C. Add a Roman numeral in parenthesis before the cation to denote the charge on cation.
D. Add the prefix mono- or di- or tri- to the cation depending on the charge.
E. Add the suffix –ate or –ite depending on the charge.

Answer 1

Transition metals in the ionic compounds are always going to make cation only because they will lose electrons and according to the number of electrons they have lost that positive charge number must be shown with cation because transition metal shows variable valency.

Complete answer:
When a metal reacts with Non-metal, it has the tendency to lose electrons and form positive ions, this positive ion is called cation and non-metal has the tendency to gain those electrons and form negative ions, this negative ion is called an anion.
Now this cation and anion will be attracted towards each-other and will bind together with this strong electrostatic force and form a molecule. Now constituent particles of this molecule are an ion, that’s why this is known as an ionic compound. Prefix mono-, di- or tri are used with non-metals when they make more than one compound with the same element. For example one oxide of nitrogen is $N{{O}_{2}}$ which is called as Nitrogen dioxide and another oxide is $NO$ which is called as nitrogen monoxide.
Suffix –ate and –ite are used with anions. For example $SO_{4}^{2-}$ is called sulphate using -ate as suffix while $SO_{3}^{2-}$ is called sulphite using –ite as suffix. Roman numeral is always added in parenthesis after the cation to denote the charge on cation.
For example, Iron(II) Sulphate. Here iron is having 2+ charge on it, that’s why after the iron, 2 is mentioned in roman numerals. It is important to mention charge in parenthesis after the Iron because Iron forms more than one type of sulphate. Other sulphate of Iron is, Iron(III) Sulphate

So correct answer for this question is Option (A)

Additional information: The elements of the second and third rows of the periodic table show gradual changes in properties across the table from left to right as expected. Electrons in the outer shells of the atoms of these elements have little shielding effects resulting in an increase in effective nuclear charge due to the addition of protons in the nucleus. Consequently, the effects on atomic properties are: smaller atomic radius, increased first ionization energy, enhanced electronegativity and more non-metallic character. This trend continues until one reaches calcium (Z=20). There is an abrupt break at this point. The next ten elements called the first transition series are remarkably similar in their physical and chemical properties. This general similarity in properties has been explained in terms of their relatively small difference in effective nuclear charge over the series. This occurs because each additional electron enters the penultimate 3d shell providing an effective shield between the nucleus and the outer 4s shell.

Note: for the transition metals it is important to show their oxidation number in parenthesis because they often form more than one compound with the same nonmetal and this mentioning of oxidation number helps us to identify which of the compound of metal and non-metal is mentioned over here.