Out of following which has the highest electronegativity ?

Options

A. H
B. Li
C. Na
D. Be

Answer

To determine which of the given elements has the highest electronegativity, we will analyze the elements provided: hydrogen (H), lithium (Li), sodium (Na), and beryllium (Be).

### Step-by-Step Solution:

1. **Understanding Electronegativity**:
- Electronegativity is defined as the tendency of an atom to attract shared electrons in a chemical bond.

2. **Trend of Electronegativity in the Periodic Table**:
- Electronegativity decreases as you move down a group (top to bottom) in the periodic table. This is because the number of electron shells increases, which reduces the effective nuclear charge felt by the valence electrons.
- Electronegativity increases as you move from left to right across a period. This is due to the increase in nuclear charge, which attracts the valence electrons more strongly.

3. **Analyzing the Given Elements**:
- **Hydrogen (H)**: Located in Group 1 and Period 1.
- **Lithium (Li)**: Located in Group 1 and Period 2.
- **Sodium (Na)**: Located in Group 1 and Period 3.
- **Beryllium (Be)**: Located in Group 2 and Period 2.

4. **Comparing Electronegativity**:
- As we move down the group from hydrogen to lithium to sodium, electronegativity decreases. Therefore, hydrogen has a higher electronegativity than both lithium and sodium.
- Beryllium, being in Group 2, has a lower electronegativity compared to hydrogen, despite being in the same period as lithium.

5. **Conclusion**:
- Based on the trends and the positions of the elements in the periodic table, hydrogen has the highest electronegativity among the given options.

### Final Answer:
**Hydrogen (H) has the highest electronegativity among the given elements.**