What is the reason why orbital 4s , becomes full of electrons before orbital 3d?

I've already underwent penile surgery twice, once for phimosis (when I was a kid) though that was just a simple cirumcision. Thing is, the circumcision left my penis with another problem, it started developing a really extreme curve downwards, I underwent surgery again that involved skin grafts...

How would I describe the hybrid orbital formed by 'mixing' one 'd', one 's' and two 'p' orbitals? I know the shapes of the individual orbitals but I don't know how they 'mix'.

OK I'm trying to do my chem hwk and it says bromine has 35 electrons and 4 orbitals... but you can't fit that many electrons in 4 orbitals I just don't understand plzz help!!

Can someone please explain how to draw orbitals for an atom and which planes they lie in. especially the p orbitals the 3 different ways they lie and how they are named i.e pxy etc. Can someone tell me how to draw the 2pz angular function and state what this tells me about the electron density...