Which has the highest electronegativity?

Options

A. `Li`
B. `Be`
C. `Mg`
D. `Na`

Explanation

To determine which element has the highest electronegativity among the alkaline earth metals, we will analyze the trend in electronegativity within the periodic table.

### Step-by-Step Solution:

1. **Identify the Elements**: The alkaline earth metals are located in Group 2 of the periodic table. The elements in this group include Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), and Barium (Ba).

2. **Understand Electronegativity Trends**:
- Electronegativity generally increases as you move from left to right across a period due to increasing effective nuclear charge.
- Electronegativity decreases as you move down a group because the atomic size increases, which reduces the nucleus's ability to attract bonding electrons.

3. **Position of Alkaline Earth Metals**:
- Beryllium (Be) is in the second period.
- Magnesium (Mg) is in the third period.
- Calcium (Ca) is in the fourth period.
- Strontium (Sr) is in the fifth period.
- Barium (Ba) is in the sixth period.

4. **Apply the Trends**:
- Since electronegativity increases from left to right and decreases down the group, we can conclude that Beryllium, being the highest up in the group, will have the highest electronegativity among the alkaline earth metals.

5. **Conclusion**: Therefore, the element with the highest electronegativity among the alkaline earth metals is **Beryllium (Be)**.

### Final Answer:
Beryllium (Be) has the highest electronegativity among the alkaline earth metals.

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