How many different orbitals can have the principal quantum number n = 3?

(a) 9

(b) 4

(c) 6

(d) 5

(e) 18

We’re being asked which of the following combinations could give the quantum numbers for the single valence electron of the copper in its ground state.

Recall that the quantum numbers are:

• **principal quantum number (n)**** ****→**** **energy level in orbitals and its value could be **any positive integer** starting from 1 to infinity.

• **angular momentum quantum number (ℓ)**** ****→ ****(l) has to be at least 1 less than n, **range of values from** 0 up to (n-1)**

▪ Each **ℓ value **corresponds to a **subshell**:

**ℓ**** = 0** → s subshell**ℓ**** = 1** → p subshell **ℓ**** = 2** → d subshell**ℓ**** = 3** → f subshell

• **magnetic quantum number (m _{ℓ})**

▪ The **m _{ℓ} values **(for each ℓ) represent an

Quantum Numbers