1) Why do we discuss electrons in terms of the probability of finding them in an orbital instead of in terms of absolute locations
2) Why are there no 1p orbitals?
3) What is the probability of finding an electron at the point where the two halves of a p-orbital come together? What is this point called?
4) Think about a helium atom. Without using actual numbers, compare the first and second ionization energies and explain why they are different. Remember that both electrons come from the 1s orbital.