Question

Why the first ionization energy of carbon atom is greater than that of boron atom whereas, the reverse is true for the second ionization energy?

Answer 1

If you see the electronic Configuration of carbon and boron you will notice that boron has only one electron in its valence shell so it would require a min. Amount of energy to remove an electron.

But for second ionisation Enthalpy boron has achieved a stable electronic configuration so it would require energy greater than carbon having Only one electron after removing a one.

Hope you get your answer.