Question

Why is the second ionisation enthalpy of Ca is more than its first ionisation enthalpy?
Why is the first ionisation enthalpy of Mg higher than Al
(See Lesson 3)​

Answer 1

Answer:

the second ionization enthalpy of calcium is higher than the first ionization enthalpy and yet calcium forms cacl2, why? 1. This is because,when Ca2+ combines with 2 Cl- ions,the lattice energy released is large enough to compensate the second and first ionisation energy of Ca. 2.

thus Mg has the first ionisation enthalpy higher than that of Al due to the fulfilled s-orbital of Mg which requires higher energy to remove the electron from the outermost shell and on the other hand Al can easily lose one electron as p-orbital has only one electron.