The number of positively charged particles in the elements A, B, C are 10, 18, 8 respectively . Identify the element which is chemically reactive?

Options

A. A
B. B
C. C
D. Both A and B

Explanation

To determine which of the elements A, B, or C is chemically reactive based on the number of positively charged particles (protons), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Number of Protons**:
- For element A: 10 protons
- For element B: 18 protons
- For element C: 8 protons

2. **Determine the Number of Electrons**:
- Since the number of protons equals the number of electrons in a neutral atom:
- Element A has 10 electrons.
- Element B has 18 electrons.
- Element C has 8 electrons.

3. **Write the Electron Configuration**:
- Element A (10 electrons): The electron configuration is 2, 8 (2 electrons in the first shell and 8 in the second shell).
- Element B (18 electrons): The electron configuration is 2, 8, 8 (2 in the first shell, 8 in the second shell, and 8 in the third shell).
- Element C (8 electrons): The electron configuration is 2, 6 (2 in the first shell and 6 in the second shell).

4. **Determine Stability**:
- An element is considered stable when its outermost shell (valence shell) is full.
- The octet rule states that atoms are most stable when they have 8 electrons in their valence shell.
- The duplet rule applies to elements with 2 electrons in their outer shell.

5. **Analyze Each Element**:
- **Element A (2, 8)**: This configuration fulfills the octet rule (8 electrons in the outer shell). Therefore, it is stable and not chemically reactive.
- **Element B (2, 8, 8)**: This configuration also fulfills the octet rule. Therefore, it is stable and not chemically reactive.
- **Element C (2, 6)**: This configuration does not fulfill the octet rule (only 6 electrons in the outer shell). It needs 2 more electrons to achieve stability.

6. **Conclusion**:
- Since Element C is the only one that does not have a full outer shell and needs to gain 2 electrons to achieve stability, it is chemically reactive.

### Final Answer:
Element C is chemically reactive.