An atom has 2 electrons in K shell, 8 electrons in L shell and 6 electrons in M shell. The number of s-electrons present in that element is

Options

A. 6
B. 5
C. 7
D. 10

Explanation

To determine the number of s-electrons present in the given atom, we can follow these steps:

### Step 1: Identify the Electron Configuration
The atom has:
- 2 electrons in the K shell (1st shell)
- 8 electrons in the L shell (2nd shell)
- 6 electrons in the M shell (3rd shell)

### Step 2: Write the Electron Configuration
The electron configuration can be written based on the distribution of electrons in the shells:
- K shell (1st shell): 2 electrons → 1s²
- L shell (2nd shell): 8 electrons → 2s² 2p⁶
- M shell (3rd shell): 6 electrons → 3s² 3p⁴

Thus, the complete electron configuration is:
\[ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^4 \]

### Step 3: Count the s-Electrons
Now, we need to count the s-electrons from the electron configuration:
- From the K shell: 2 electrons (1s²)
- From the L shell: 2 electrons (2s²)
- From the M shell: 2 electrons (3s²)

Adding these together:
\[ 2 (from \, K) + 2 (from \, L) + 2 (from \, M) = 6 \, s-electrons \]

### Final Answer
The number of s-electrons present in that element is **6**.

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