Question

The correct order of the first ionization enthalpies is:
a.) Mn < Ti < Zn < Ni
b.) Ti < Mn < Ni < Zn
c.) Zn < Ni < Mn < Ti
d.) Ti < Mn < Zn < Ni

Answer 1

Hint:. The amount of energy which is required to remove an electron from an isolated gaseous atom or a molecule is called ionization energy or ionization potential. It gives ideas about the chemical reactivity of atoms or molecules.

Complete step by step answer:
Ionization energy or ionization potential is the minimum amount of energy which is required from an electron to come out from the influence of the nucleus. Ionization energy increases with the increase in the atomic number when we move from left to right in a period and it decreases when we move down the group.
First ionization potential is the energy required to remove the first electron or one electron from the valence orbital of the atom or an ion. Let’s consider the electronic configuration of all the given options.

Electronic configuration of manganese: $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{5}}$
Electronic configuration of titanium: $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{2}}$
Electronic configuration of zinc: $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{10}}$
Electronic configuration of nickel: $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{8}}$

The value of ionization enthalpy for Zn is 906 Kj/mol and for Ni is 736 kj/mol then for Mn is 717 kj/mol and for Ti is 656 kj/mol also zinc has a fully filled electronic configuration which is most stable hence the value of ionization enthalpy will be highest for zinc.
So, the correct answer is “Option B”.

Note: This order is only valid for the first ionization enthalpy or energy. For the second ionization enthalpy the order changes because losing an electron makes some of the compound stable and some unstable. This affects the order of ionization enthalpy. The element having the half-filled or fully filled electronic configurations are most stable.