NEET2026ChemistryChapterActual
Which of the following represents the correct increasing order of covalent character for the given transition metal monoxides?
Options
- ANiO < CoO < FeO < MnO
- BMnO < FeO < CoO < NiO
- CMnO < CoO < FeO < NiO
- DFeO < MnO < NiO < CoO
Correct answer
B. MnO < FeO < CoO < NiO
Step-by-step solution
According to Fajan's rules, the covalent character of an ionic compound increases with the polarizing power of the cation. The polarizing power of a cation is inversely proportional to its ionic radius when the charge is constant. For the given monoxides, the cations are Mn ²⁺ , Fe ²⁺ , Co ²⁺ , and Ni ²⁺ . All have a +2 charge. Along the 3d transition series, the ionic radius decreases from left to right due to an increase in effective nuclear charge. The order of ionic radii is Mn ²⁺ > Fe ²⁺ > Co ²⁺ > Ni ²⁺ . Cons