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

The order of second ionisation enthalpies are Cr > Mn > V > Ti

• The ionisation enthalpy of Ti is [Ar]₁₈ 3d²4s²

• The ionisation enthalpy of V is [Ar]₁₈ 3d³4s²

• The ionisation enthalpy of Cr is [Ar]₁₈ 3d⁵4s¹

• The ionisation enthalpy of Mn is [Ar]₁₈ 3d⁵4s²

• While we move across a period in periodic table ionisation enthalpy increases

• But Chromium has more symmetrical electronic configuration which makes it having higher second ionisation enthalpy than Manganese

• The correct order is Cr > Mn > V > Ti

Answer 2

Answer:Correct option (c) Cr > Mn > V > Ti Explanation : Electronic configuration of the given elements are In general, ionization potential (both 1st and 2nd) 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

Explanation: