The first element of the group 1 and 2 are different from other members of the respective group.Their behaviour is more similar to the second element of the following groups,What is this relationship known as ?

Options

A. Anomalous relationship
B. Periodic relationship
C. Diagonal relationship
D. Chemical relationship

Explanation

To solve the question regarding the relationship between the first elements of groups 1 and 2 and their similarity to the second elements of the following groups, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Group 1 and Group 2 Elements**:
- Group 1 elements (alkali metals) include Lithium (Li), Sodium (Na), Potassium (K), etc.
- Group 2 elements (alkaline earth metals) include Beryllium (Be), Magnesium (Mg), Calcium (Ca), etc.
- The first elements of these groups (Li and Be) exhibit properties that are different from the rest of their group members.

2. **Identifying the Behavior of Li and Be**:
- Lithium (Li) behaves differently compared to Sodium (Na) and Potassium (K).
- Beryllium (Be) shows different properties compared to Magnesium (Mg) and Calcium (Ca).

3. **Comparing with Second Elements of the Following Groups**:
- The behavior of Lithium is more similar to Magnesium (the second element of the next group).
- The behavior of Beryllium is more similar to Aluminum (the second element of the next group).

4. **Defining the Relationship**:
- The relationship where the first element of one group shows similarities to the second element of the next group is known as the **diagonal relationship**.
- This diagonal relationship occurs due to the gradual change in properties as you move across periods and down groups in the periodic table.

5. **Conclusion**:
- Based on the analysis, the correct answer to the question is **diagonal relationship**.

### Final Answer:
The relationship is known as **diagonal relationship**.

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