Well, I can tell you something about ionic and covalent bonds, but not really anything about polar covalent bonds.
Ionic bonds are formed when a metal and a non-metal react. One gives the electrons and one takes the electrons. This forms two charged atoms, which atrtact together. One is positive and one is negative. These are ions, and when they stick together, they form ionic bonds!
The covalent bond is something differet. This usually happens when too much energy has to be used to either give or take the electrons. So, in that case, they share the electrons. Also, it may happen when a hydrogen atom, like the example in the first post, would end up with no electrons.
They do his all to ge ta full outer shell, remember.
As for the other questions, I have no absolute idea