Q. Which one of the following does not correctly represent the correct order of the property indicated against it?
A) Ti < V < Cr < Mn : increasing number of oxidation states
B) Ti³⁺ < V³⁺ < Cr³⁺ < Mn³⁺ : increasing magnetic moment
C) Ti < V < Cr < Mn : increasing melting points
D) Ti < V < Mn < Cr : increasing 2nd ionization enthalpy
Explanation
[Solution from source] Manganese has a much lower melting point (about 1246 °C) than chromium (about 1907 °C) because its stable 3d⁵4s² configuration weakens metallic bonding, so Ti < V < Cr < Mn for melting point is wrong. The other orders are right: Cr has the highest 2nd ionisation enthalpy (removing an electron from stable 3d⁵), and unpaired electrons rise from d¹ to d⁴ across Ti³⁺ to Mn³⁺. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.