Question

The first ionisation energy of carbon atom is greater than thatof boron atom whereas reverse is true for the second ionisation energy .explain

Answer 1

Ionisation energy is the energy

required to remove an outermost

electron from isolated neutral

gaseous atom .

Configuration of Carbon and Boron

C=>1s2 ,2s2 2p2

B=>1s2,2s2 2p1

Since carbon has more no. Of e-mail

in outermost subshell ,I.E1 of carbon

is greater than I.E1 of boron

After giving 1e-

Electronic configuration

C=>1s2 ,2s2 2p1

And ,B=>1s2 ,2s2

Since, Boron subshell is completely

filled ,it will require more energy to

remove an electron in compare to

carbon .

So,I.E2of Boron is greater than I.E2of

Carbon.

Hope it helps.