Question

The correct order of decreasing second ionisation enthalpy of Ti(22), V(23), Cr(24) and Mn(25) is:

(a) Cr > Mn > V > Ti
(b) V > Mn > Cr > Ti
(c) Mn > Cr > Ti > V
(d) Ti > V > Cr > Mn

Answer 1

(a) Cr > Mn > V > Ti

Electronic configuration of the given elements are

Ti = [Ar] 3d² 4s²; V = [Ar] 3d³ 4s² Cr = [Ar] 3d⁵ 4s¹; Mn = [Ar] 3d⁵ 4s²

Their effective nuclear charge increases from Ti to Mn. Hence their first IE increases in the same order, i.e., Mn > Cr > V > Ti. However after the removal of first electron, chromium attains the stable configuration [3d⁵] and hence, it has very high second IE. For the remaining elements the trend remains the same. Thus, the second IE will be in the order.

Cr > Mn > V >Ti