Assertion (A): Alkali metals do not occur in native state.
Reason (R ): Alkali metlas are highly reactive elements.

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 not the correct explanation of (A).
C. If (A) is correct, but (R ) is incorrect.
D. If (A) is incorrect, but (R ) is correct.

Answer

To solve the assertion and reason question regarding alkali metals, we can break it down into a step-by-step analysis.

### Step 1: Understand the Assertion
The assertion states that "Alkali metals do not occur in native state." This means that alkali metals are not found in their elemental form in nature.

**Hint:** Consider why certain elements are not found in their pure form in nature.

### Step 2: Understand the Reason
The reason provided is that "Alkali metals are highly reactive elements." This indicates that these metals readily react with other substances, which prevents them from existing in their elemental state.

**Hint:** Think about the properties of alkali metals and how reactivity influences their occurrence in nature.

### Step 3: Connect the Assertion and Reason
Now, we need to connect the assertion and the reason. Alkali metals have one electron in their outermost shell, which makes them highly reactive. As we move down the group, the reactivity increases due to lower ionization energies, making it easier for these metals to lose their outer electron. Because of this high reactivity, they do not remain in their native state and are usually found in compound forms.

**Hint:** Reflect on how the electronic configuration of alkali metals contributes to their reactivity.

### Step 4: Conclusion
Both the assertion and the reason are correct. The reason provided accurately explains why alkali metals do not occur in their native state. Therefore, the correct conclusion is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

**Final Answer:** Both assertion and reason are correct, and the reason is the correct explanation of the assertion.