How many electrons can reside in all of the 2p orbitals?

How are orbitals grouped together?

What do all the elements in group 1 on the periodic table have in common in their outermost orbital?

Why do elements above and below each other (the same group) on the periodic table have similar properties?

What does an energy-level diagram show?

How many p orbitals can be found on each energy level?

Why are the arrows used to denote electrons in an atomic orbital facing in opposite directions?

How many electrons can occupy each atomic orbital?

How can an electron travel through the node of a d orbital?