The most common oxidation state of an element is -2. The number of electrons present in its outermost shell is

Options

A. 2
B. 4
C. 6
D. 8

Answer

To solve the question regarding the most common oxidation state of an element being -2 and determining the number of electrons present in its outermost shell, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Oxidation State**: The oxidation state of an element indicates how many electrons it has gained or lost compared to its neutral state. An oxidation state of -2 means the element has gained 2 electrons.

2. **Achieving Noble Gas Configuration**: When an element gains electrons to achieve a stable configuration, it typically aims to complete its outermost shell (octet rule). For most elements, this means having 8 electrons in their outermost shell.

3. **Setting Up the Equation**: Let the number of valence electrons (electrons in the outermost shell) of the element be represented as \( X \). After gaining 2 electrons, the total number of electrons in the outermost shell becomes \( X + 2 \).

4. **Completing the Octet**: Since the element achieves a stable configuration after gaining 2 electrons, we can set up the equation:
\[ X + 2 = 8 \]

5. **Solving for X**: Rearranging the equation gives:
\[ X = 8 - 2 \]
\[ X = 6 \]

6. **Conclusion**: Therefore, the number of electrons present in the outermost shell of the element is 6.

### Final Answer:
The number of electrons present in its outermost shell is **6**.

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