AP EAMCET Engineering 22 Sep 2020 Shift 1 Paper

As we go from left to right in period the ionisation potential increases but Be and B are exception as the Be has 1s2,2s2 and boron has 1s2,2s2,2p1 so it's easy to remove electron from boron than beryllium decreasing order of their first ionisation enthalpies. C>Be>B>Li