Question

explain why the third ionization enthalpy of manganese is exceptionally high

Answer 1

it's valence configuration is
4s2 3d5 implies we remove from the 2e from 4s2 then comes 3d5 which is half filled which is stable

Answer 2

Explanation:

Ionization energy is the amount of energy released when an electron is removed from a neutral or gaseous ion.

Atomic number of manganese is 25 and its electronic configuration is as follows.

      $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{5}$

So, when two electrons are removed then configuration of manganese becomes $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{0}3d^{5}$.

Now, there are 5 electrons in 3d orbital and therefore, it is stable in nature.

When another electron is removed then ionization energy will become exceptionally high because the 3d orbital is stable and thus high heat or energy has to be provided in order to remove an electron from it.