1. (a) There are four subshells in the fourth shell, corresponding to the four possible values of l (0, 1, 2, and 3).
(b) These subshells are labeled 4s, 4p, 4d, and 4f.
(c) There is one 4s orbital (when l = 0, there is only one possible value of ml: 0). There are three 4p orbitals (when l = 1, there are three possible values of ml: 1, 0, and -1). There are five 4d orbitals (when l = 2, there are five allowed values of ml: 2, 1, 0, -1, -2). There are seven 4f orbitals (when l = 3, there are seven permitted values of ml: 3, 2, 1, 0, -1, -2, -3).
2. [Ne]3s23p3 is the electron configuration of a(n) Phosphorus (P) atom.
3. All of the alkaline metals have a valence shell electron configuration one.
4. At maximum, an d-subshell can hold ten electrons.
5. The complete electron configuration of sulfur, element 16, is 1s2 2s2 2p6 3s2 3p4.
6. The angular momentum quantum number for the outermost electrons in a manganese atom in the ground state is 2.
7. The electron configuration of the valence electrons of an atom in its ground state is ns2np3. This atom is a group 5 element.