Two electrons occupying the same orbital are distinguished by
- azimuthal quantum number
- spin quantum number
- principal quantum number
- magnetic quantum number
Answer
(2) spin quantum number
Solution
An orbital is defined by three quantum numbers n, l and ml.
⇒ Two electrons in the same orbital have the same n, l and ml.
As per NCERT (Pauli exclusion principle), no two electrons in an atom can have the same set of all four quantum numbers.
∴ They must differ in spin quantum number: ms = + 12 and - 12.
Answer: (2)