The set of quantum numbers not possible to an electron is

Options

A. `1,1,1,+1//2`
B. `1,0,0+1//2`
C. `1,0,0-1//2`
D. `2,0,0+1//2`

Explanation

To determine the set of quantum numbers that is not possible for an electron, we need to understand the rules governing quantum numbers:

1. **Principal Quantum Number (n)**: This can take any positive integer value (1, 2, 3,...).
2. **Azimuthal Quantum Number (l)**: This can take integer values from 0 to (n-1). Therefore, l must always be less than n.
3. **Magnetic Quantum Number (m)**: This can take integer values from -l to +l, including zero.
4. **Spin Quantum Number (s)**: This can take values of +1/2 or -1/2.

### Step-by-Step Solution:

1. **Identify the given quantum numbers**: We need to analyze the quantum numbers provided in the options to find which set is not possible.

2. **Check the conditions for each option**:
- **Option A**: n = 1, l = 1, m = 1, s = 1
- Here, l is equal to n (l = 1 and n = 1). According to the rules, l must be less than n. Therefore, this set is **not possible**.

- **Option B**: n = 1, l = 0, m = 0, s = 1.5
- Here, l is less than n (l = 0 and n = 1). However, the spin quantum number s = 1.5 is not allowed, as s can only be +1/2 or -1/2. Therefore, this set is also **not possible**.

- **Option C**: n = 1, l = 0, m = 0, s = -1/2
- Here, l is less than n (l = 0 and n = 1). The spin quantum number s = -1/2 is allowed. Therefore, this set is **possible**.

3. **Conclusion**: The only set of quantum numbers that is not possible is **Option A** (n = 1, l = 1, m = 1, s = 1).

### Final Answer:
The set of quantum numbers that is not possible for an electron is **Option A**: (n = 1, l = 1, m = 1, s = 1).