#### CHAPTER 12 ATOMS

Quantum numbers

Quantum numbers are the numbers required to completely specify the state of the electrons.

There are four quantum number associated with each electron,

• Principle quantum number (n) can have value 1, 2, … ∞

• Orbital angular momentum quantum number l can have value 0,1, 2, … ,(n – 1).

• Magnetic quantum number (ml) which can have values – l to l.

• Magnetic spin angular momentum quantum number (ms) which can have only two value ± $\frac{1}{2}$.