Assertion: The melting and boiling points of the alkali metals are low.
Reason: Alkali metals have weak metalli bonding.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To analyze the given assertion and reason, we can break down the problem into a step-by-step solution.

### Step 1: Understand the Assertion
The assertion states that "The melting and boiling points of the alkali metals are low."
- Alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).
- These metals are known for having low melting and boiling points compared to other metals.

### Step 2: Examine the Reason
The reason provided is "Alkali metals have weak metallic bonding."
- Metallic bonding in metals involves the attraction between positively charged metal ions and a sea of delocalized electrons.
- In alkali metals, due to their larger atomic size and the presence of only one valence electron, the metallic bonds are relatively weak.

### Step 3: Correlate Assertion and Reason
- The low melting and boiling points of alkali metals can indeed be attributed to the weak metallic bonding.
- Since the bonds between the metal atoms are weak, less energy is required to overcome these bonds, resulting in lower melting and boiling points.

### Step 4: Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, the correct answer is that both statements are true and the reason explains the assertion.

### Final Answer
The correct option is A: Both assertion and reason are true, and the reason correctly explains the assertion.

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