A neutral atom of an element has `2K,8L, 9M` and `2N` electrons .The atomic number of element is :

Options

A. 20
B. 21
C. 22
D. 23

Explanation

To find the atomic number of the element based on the distribution of its electrons in different shells, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Electron Distribution**:
The problem states that the neutral atom has the following distribution of electrons:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 9 electrons
- N shell: 2 electrons

2. **Count the Total Number of Electrons**:
To find the atomic number, we need to sum up all the electrons present in the different shells:
\[ \text{Total electrons} = \text{Electrons in K} + \text{Electrons in L} + \text{Electrons in M} + \text{Electrons in N} \]
\[ \text{Total electrons} = 2 + 8 + 9 + 2 \]

3. **Perform the Addition**:
Now, we add the numbers:
\[ 2 + 8 = 10 \]
\[ 10 + 9 = 19 \]
\[ 19 + 2 = 21 \]

4. **Determine the Atomic Number**:
Since the atom is neutral, the number of protons is equal to the number of electrons. Therefore, the atomic number of the element is:
\[ \text{Atomic Number} = 21 \]

### Final Answer:
The atomic number of the element is **21**.

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