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Question
Explain the deviation in ionisation enthalpy of some elements from the general trend by using the given figure.

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Solution
The deviation in the ionization enthalpy of some elements from the general trend can be explained by the points as given below:-
(i) The fully filled and half-filled orbital provide extra stability due to the symmetry.
(ii) The effective nuclear charge.
(iii) The \[\ce{e- - e-}\] repulsion which lead to instability.
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