Yes, I meant Mg has electron in 2p orbital.
Boron does have 1 electron in 2p orbital (I meant to say all elements which has no electron p orbital at all violates octet rule, H, He,Li, Be) and it violates octet rule for having too few electrons, if it even shares all electrons still can't achieve octet.
You can't say outer shell for period one elements, it only has one shell and have electrons in 1s orbital.
Elements: H, He
the outer shell is the valence electrons and they are very loosely bound to the nucleus - less force by the nucleus on the valence electrons, so valence shell's electrons are exchanged first in any reaction.
As you know group I has 1 valance electron and 2 has 2 and so forth.
Lithium's 2nd shell is outermost and it contain 2s orbital holding 1 electron, which it can lose to become Li+ ion.
Be has 2 electron in outermost shell.
Chad mentions in his video all elements can have all type of orbital. For example Hydrogen has s,p,d,f all orbitals but doesn't have enough electrons to be placed in p,d,f orbital,
I might be confusing you more, but Please watch Chad's videos for Chem and Ochem.
They will clear out most of the confusions.