First ionisation potential of C- atom is greater than that of B atom , where as the revers is true is for second ionisation potential.

First ionisation potential of C- atom is greater than that of B atom ,

1.	First ionisation potential of C- atom is greater than that of B atom , where as the revers is true is for second ionisation potential.
Answer» Solution :Electron configuration of carbon `(Z=6)1s^(2)2s^(2)2p^(2)` Electron configuration of Boron `(Z=5)1s^(2)2s^(2)2p^(1)`. The size of a carbon atom is SMALLER than boron. So the valence electron of carbon has greater nuclear charge than that of boron . Hence the first I.E of carbon is greater than that of boron. However , the second IONIZATION enthalphy of boron is higher than that of carbon . This is because after losing 1 electron , Boron has a fully FILLED orbital so greater amount of energy will be needed to REMOVE an electron from boron . So in this case , the second I.E of boron is higher than that of carbon.