Question

If \(n,l,m\) and \(s\) represent the symbols of quantum numbers, the impossible quantum number set for the electron in terms of \(n,l,m\) and \(s\) respectively is

• A. \(2,0,-1,+\frac{1}{2}\)
• B. \(3,0,0,-\frac{1}{2}\)
• C. \(4,1,+1,+\frac{1}{2}\)
• D. \(3,2,-1,-\frac{1}{2}\)

Hint:

For a given \(l\), magnetic quantum number \(m\) can only vary from \(-l\) to \(+l\).

Answer 1

The Correct Option is A

Concept:
Quantum numbers must obey certain rules: \[ n=1,2,3,\ldots \] \[ l=0,1,2,\ldots,(n-1) \] \[ m=-l,\ldots,0,\ldots,+l \] \[ s=\pm\frac{1}{2} \]

Step 1: Check option (A): \[ n=2,\quad l=0,\quad m=-1,\quad s=+\frac{1}{2} \]

Step 2: If \(l=0\), then the only possible value of \(m\) is: \[ m=0 \]

Step 3: But option (A) gives: \[ m=-1 \] This is not allowed.

Step 4: Therefore, option (A) is an impossible set of quantum numbers. \[ \boxed{2,0,-1,+\frac{1}{2}} \]