The electronic configuration of an atom is 2,8,2 . The number of valence electrons in the atom is

Options

A. 10
B. 12
C. 8
D. 2

Answer

To determine the number of valence electrons in an atom with the electronic configuration of 2, 8, 2, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Electronic Configuration**:
The electronic configuration given is 2, 8, 2. This means:
- The first shell (K shell) has 2 electrons.
- The second shell (L shell) has 8 electrons.
- The third shell (M shell) has 2 electrons.

2. **Determine the Outermost Shell**:
The outermost shell is the shell that is farthest from the nucleus. In this case, the outermost shell is the third shell (M shell).

3. **Count the Electrons in the Outermost Shell**:
In the M shell, there are 2 electrons.

4. **Define Valence Electrons**:
Valence electrons are the electrons present in the outermost shell of an atom. They are important because they are involved in chemical bonding.

5. **Conclusion**:
Since the M shell has 2 electrons, the number of valence electrons in this atom is 2.

### Final Answer:
The number of valence electrons in the atom is **2**.

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