12. a) Write the full electron configuration for the magnesium atom. b) Label and provide a point form explanation for each of the significant parts of the electron configuration.

ow does probability ?t into the description of the atom?

Suppose that the spin quantum number did not exist, and therefore only one electron could occupy each orbital of a many-electron atom. Give the atomic numbers of the first three noble-gas atoms in this case.

What type of electron orbital (i.e., s, p, d, or f) is designated by (a) n=3,l=1,m l =1?(b) n=5,l=0,m l =0? (c) n=6,l=4,m l =4?

• rank various orbitals in terms of size and energy.

6.10 Define the term refraction.

The first ionization energy of helium is 2370kJmol1 , the highest for any element. (a) Define ionization energy and discuss why for helium it should be so high. (b) Which element would you expect to have the highest second ionization energy? Why? (c) Suppose that you wished to ionize some helium by shining electromagnetic radiation on it. What is the maximum wavelength you could use?