An atom has 2K, 8 L, 11 M, 2N electrons, the total number of s-electrons will be

Options

A. 6
B. 8
C. 10
D. 4

Explanation

To find the total number of s-electrons in the given atom with the electron configuration of 2K, 8L, 11M, and 2N, we can follow these steps:

### Step 1: Understand the Electron Configuration
The notation given indicates the distribution of electrons in different energy levels (shells) and subshells. The shells are labeled K, L, M, and N, corresponding to the principal quantum numbers n=1, 2, 3, and 4, respectively.

### Step 2: Count the Total Number of Electrons
We need to sum the electrons in each shell:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 11 electrons
- N shell: 2 electrons

Total electrons = 2 (K) + 8 (L) + 11 (M) + 2 (N) = 23 electrons

### Step 3: Determine the Electronic Configuration
Now, we can write the electronic configuration based on the total number of electrons (23):
1. Fill the 1s orbital: 1s² (2 electrons)
2. Fill the 2s orbital: 2s² (2 electrons)
3. Fill the 2p orbital: 2p⁶ (6 electrons)
4. Fill the 3s orbital: 3s² (2 electrons)
5. Fill the 3p orbital: 3p⁶ (6 electrons)
6. Fill the 4s orbital: 4s² (2 electrons)
7. Fill the 4p orbital: 4p² (2 electrons)

The electronic configuration is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4p²

### Step 4: Identify the s-Electrons
Now, we need to identify the number of electrons in the s orbitals:
- 1s: 2 electrons
- 2s: 2 electrons
- 3s: 2 electrons
- 4s: 2 electrons

Total s-electrons = 2 (from 1s) + 2 (from 2s) + 2 (from 3s) + 2 (from 4s) = 8 s-electrons.

### Final Answer
The total number of s-electrons in the atom is **8**.

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