When we talk about the electronic configuration of boron , sulphur , nitrogen.
What I got to learn new was about their hybridisation. For example , boron has electronic configuration as $1s^2 2s^2 2p^1$.now , there is one pared electron at 2s^2 and one unpaired electron at 2p1.
Now , during a reaction of boron with an element. It can make one of the paired electron shift to 2p1 orbital and thus form 3 unpaired electrons.
I want to know what forces the orbitals to make this happen.