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

Question

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

(a) Mn > Cr > Ti > V

(b) Ti > V > Cr > Mn

(c) Cr > Mn > V > Ti

(d) V > Mn > Cr > Ti

Answer 1

Correct option (c) Cr > Mn > V > Ti

Explanation :

Electronic configuration of the given elements are

In general, ionization potential (both 1^st and 2^nd) increases from left to right across the period due to increase in effective nuclear charge. On this basis. the second IP values should exhibit the trend:

Mn > Cr > V > Ti 

But the actual observed order is:

Cr > Mn > V > Ti

Practically, only chromium is exceptional and rest others show the normal trend. This exceptional behaviour of chromium is due to the stable configuration (3d⁵) that it achieves after the loss of first electron.