Question

Please answer this ...

Answer 1

Answer:

Explanation:

isoelectronic species means they have same no. of electrons

you can verify it

and ionisation enthalpy are directly proportional to nuclear charge and inversely proportional to atomic radii note in case of half filled shell or full filled shell the ionisation enthalpy will be more than that next ones

radius inversely proportional to charge

means option 2 for @question 20