The electrons present in K-shell of the atom will differ in

Options

A. principal quantum number
B. azimuthal quantum number
C. magnetic quantum number
D. spin quantum number

Explanation

To solve the question, "The electrons present in K-shell of the atom will differ in," we need to analyze the characteristics of electrons in the K-shell, which is the first energy level of an atom.

### Step-by-Step Solution:

1. **Identify the K-shell**:
- The K-shell corresponds to the principal quantum number \( n = 1 \). It is the closest shell to the nucleus and can hold a maximum of 2 electrons.

2. **Determine the Quantum Numbers**:
- For the K-shell, the azimuthal quantum number \( l \) is always 0 (since it is an s orbital).
- The magnetic quantum number \( m \) is also 0 (as \( m \) can take values from \(-l\) to \(+l\), and since \( l = 0 \), \( m \) can only be 0).

3. **Consider the Spin Quantum Number**:
- The only quantum number that can differ for the two electrons in the K-shell is the spin quantum number \( s \).
- The spin quantum number can have two values: \( +\frac{1}{2} \) and \( -\frac{1}{2} \). According to the Pauli Exclusion Principle, two electrons occupying the same orbital must have opposite spins.

4. **Conclusion**:
- Therefore, the electrons in the K-shell will differ in their spin quantum number. One electron will have a spin of \( +\frac{1}{2} \) and the other will have a spin of \( -\frac{1}{2} \).

### Final Answer:
The electrons present in the K-shell of the atom will differ in their spin quantum number.

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