Solutions/Answers to Exercises
Exercise 1. Assign 4 quantum numbers to each of the following electrons.
n = 3, l = 0, ml = 0, ms = +1/2 or -1/2
b) a 4d electron
n = 4, l = 2, ml = -2, -1, 0, +1, or +2, ms = +1/2 or -1/2
c) a 4f electron
n = 4, l = 3, ml = -3, -2, -1, 0, +1, +2, or +3, ms = +1/2 or -1/2
d) a 3p electron
n = 3, l = 1, ml = -1, 0, or +1, ms = +1/2 or -1/2
Exercise 2. Which of the following sets of quantum numbers are not allowed. Explain your answer.
Not allowed. ml cannot be equal to -4.
b) n = 2, l = 3, ml = 0, ms = +1/2
Not allowed. l must not exceed the value of n. l must have values from 0 to n – 1.
c) n = 3, l = 2, ml = -1, ms = +1/2
These are allowed.
Exercise 3. What is the maximum number of electrons allowed in n = 4? n = 6?
n = 4 can hold a maximum of 32 electrons. n = 6 can hold a maximum of 2 x 62 = 72 electrons.
Exercise 4. Assign 4 quantum numbers to each of the electrons in a carbon atom.
The carbon atom has 6 electrons.
Electron 1: n = 1, l = 0, ml = 0, ms = +1/2
Electron 2: n = 1, l = 0, ml = 0, ms = -1/2
Electron 3: n = 2, l = 0, ml = 0, ms = +1/2
Electron 4: n = 2, l = 0, ml = 0, ms = -1/2
Electron 5: n = 2, l = 1, ml = -1, ms = +1/2
Electron 6: n = 2, l = 1, ml = 0, ms = +1/2
Exercise 5. Assign 4 quantum numbers for the outermost 2 electrons of germanium, Ge.
the two outermost electrons are in 4 p orbitals.
Electron 1: n = 4, l = 1, ml = -1, ms = +1/2
Electron 2: n = 4, l = 1, ml = 0, ms = +1/2