An element of the 3d transition series shows two oxidation states, X and Y, which differ by two units. Consider the following statements:
(A) The compounds in oxidation state X are more ionic if X > Y.
(B) The compounds in oxidation state X are more ionic if X < Y.
(C) The compounds in oxidation state Y are more covalent if X < Y.
(D) The compounds in oxidation state Y are more covalent if Y < X.
Which of the statements given above are correct?
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (B) and (C) only
For the compounds of one transition metal, ionic character decreases as the oxidation number increases. So of the two states, the lower one gives the more ionic compounds and the higher one the more covalent compounds; for manganese, MnO is ionic while \( \ce{Mn2O7} \) is a covalent oil.
(A) The compounds in oxidation state X are more ionic if X > Y. — False. If X > Y, X is the higher state, so its compounds are less ionic.
(B) The compounds in oxidation state X are more ionic if X < Y. — True. If X < Y, X is the lower state, so its compounds are more ionic.
(C) The compounds in oxidation state Y are more covalent if X < Y. — True. If X < Y, Y is the higher state, so its compounds are more covalent.
(D) The compounds in oxidation state Y are more covalent if Y < X. — False. If Y < X, Y is the lower state, so its compounds are more ionic, not more covalent.
NCERT (2026-27 edition):
4.4.1 Oxides and Oxoanions of Metals – “… All the metals except scandium form MO oxides which are ionic. … As the oxidation number of a metal increases, ionic character decreases. In the case of Mn, Mn2O7 is a covalent green oil.”