Question

An element of 3d- transition series shows two oxidation states x and y, differ by two units then:
A. Compounds in oxidation state x are ionic if x > y
B. Compounds in oxidation state x are ionic if x < y
C. compounds in oxidation state y are covalent if x < y
D. compounds in oxidation state y are covalent if y < x

Answer 1

Hint: The Transition elements have valence electrons in 3d orbital and show various oxidation states due to the presence of high number of valence electrons in 3d orbital and loosely bound electrons in 4s orbital.

Complete step by step answer:
 - In the question it is given that an element of 3d- transition series shows two oxidation states x and y and they differ by two units in oxidation states.
- Generally the transition element with lower oxidation state is ionic in nature and the transition element with higher oxidation state is covalent in nature.
- Means the transition metal ion which has an oxidation state is x, is ionic in nature and the same transition metal which has a high oxidation state is y, is covalent in nature.
- Coming to the given options, option A, Compounds in oxidation state x are ionic if x > y. It is wrong because x is a lower oxidation state of transition metal ions. If x < y then the transition metal ion is ionic in nature.
- Coming to option B, Compounds in oxidation state x are ionic if x < y. It is correct because in less oxidation state transition metal ions are ionic in nature.
- Coming to option C, compounds in oxidation state y are covalent if x < y. It is also correct because in high oxidation state transition metal ions are covalent in nature.
- Coming to option D, compounds in oxidation state y are covalent if y < x. It is wrong because x is the lower oxidation state of transition metal ions.
So, the correct answer is “OptionB and C”.

Note: In higher oxidation states, transition metal ions are more positive in nature over the atom and result in smaller size. Effect of high charge and smaller size have a tendency to employ more electric field therefore moves more closer to the electrons present in the surrounding atom causing an increase in the covalent character. Covalent bond is nothing but the sharing of electrons.