The order of first ionisation energies of the elements Li,Be,B,Na is
Li > Be > B > Na
Na > Li > B > Be
Be > B > Li > Na
Be > Li > B > Na
outer E.C. of boron is 2p1 and outer E.C. of li is 2s1 thats why li has highest I.E. than boron because li has half filled orbital and half filled orbital has higher I.E. than partial filled