Assertion : Noble gases are chemically inert
Reason :All noble gases have `ns^(2)np^(6)` valence shell electronic configuration

Options

A. If both (A) and (R ) are correct and (R ) is the correct explanation of (A)
B. If both (A) and (R ) are correct,but (R ) is the correct explanation of (A)
C. If (A) is correct but (R ) is incorrect
D. If (A) is incorrect but (R ) is correct

Explanation

To analyze the assertion and reason provided in the question, we will break down the statements and evaluate their validity step by step.

### Step 1: Understanding the Assertion
The assertion states that "Noble gases are chemically inert."

- **Explanation**: Noble gases, which belong to Group 18 of the periodic table, are known for their lack of reactivity. This is primarily due to their complete valence shell, which makes them stable and unlikely to form chemical bonds with other elements.

### Step 2: Evaluating the Reason
The reason given is "All noble gases have `ns^(2)np^(6)` valence shell electronic configuration."

- **Explanation**: The general electronic configuration for noble gases is indeed `ns^(2)np^(6)`, which indicates that they have a full outer shell of electrons. This configuration contributes to their chemical inertness. However, there is an exception: Helium (He), which has the electronic configuration `1s^(2)`. Helium does not have any p electrons, yet it is still considered a noble gas due to its complete s orbital.

### Step 3: Conclusion
- The assertion is **correct**: Noble gases are chemically inert.
- The reason is **incorrect**: Not all noble gases have the `ns^(2)np^(6)` configuration due to the exception of helium.

### Final Evaluation
- Since the assertion is true and the reason is false, the overall statement is that the assertion is correct, but the reason does not support the assertion.

### Summary
- **Assertion**: True
- **Reason**: False