Assertion: Elements in the same vetical column have similar properties.
Reason: Periodic properties of elements is a function of atomic number

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

### Step-by-Step Text Solution:

1. **Understanding the Assertion**: The assertion states that elements in the same vertical column (group) of the periodic table have similar properties. This is a fundamental concept in chemistry, particularly in the study of the periodic table.

2. **Understanding the Reason**: The reason given is that periodic properties of elements are a function of atomic number. This refers to the modern periodic law, which states that the properties of elements are periodic functions of their atomic numbers.

3. **Connecting Assertion and Reason**: In the modern periodic table, which was developed by Moseley, elements are arranged in order of increasing atomic number. Elements in the same group have similar valence electron configurations, which leads to similar chemical properties.

4. **Evaluating the Truth of Each Statement**:
- The assertion is true: Elements in the same vertical column do indeed have similar properties due to their similar valence electron configurations.
- The reason is also true: The periodic properties of elements are indeed a function of atomic number, as per Moseley's arrangement of the periodic table.

5. **Determining the Relationship**: Although both the assertion and the reason are true, the reason does not correctly explain the assertion. The similarity in properties is primarily due to the similar electron configurations, not just the atomic number alone.

6. **Conclusion**: Therefore, the assertion is true, and the reason is true, but the reason is not a correct explanation of the assertion.

### Final Answer:
- Assertion: True
- Reason: True
- Explanation: The reason is not a correct explanation for the assertion.

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