In comparison to B, Be has

Options

A. greater nuclear charge and lesser first ionization enthalpy
B. greater nuclear charge and greater first ionization enthalpy
C. lesser nuclear charge and greater first ionization enthalpy
D. lesser nuclear charge and lesser first ionization enthalpy

Explanation

To solve the question "In comparison to B, Be has", we need to analyze the properties of Beryllium (Be) and Boron (B) based on their atomic structure and ionization energy.

### Step-by-Step Solution:

1. **Identify the Elements**:
- Beryllium (Be) has an atomic number of 4.
- Boron (B) has an atomic number of 5.

2. **Electron Configuration**:
- The electron configuration of Beryllium (Be) is \(1s^2 2s^2\).
- The electron configuration of Boron (B) is \(1s^2 2s^2 2p^1\).

3. **Nuclear Charge**:
- The nuclear charge is determined by the number of protons in the nucleus.
- Beryllium has 4 protons, while Boron has 5 protons.
- Therefore, Boron has a greater nuclear charge than Beryllium.

4. **First Ionization Enthalpy**:
- The first ionization enthalpy is the energy required to remove the outermost electron.
- Beryllium has a stable electron configuration with fully filled \(1s\) and \(2s\) orbitals.
- Boron, on the other hand, has an unfilled \(2p\) orbital. When Boron loses one electron, it achieves a stable configuration of \(1s^2 2s^2\).
- Consequently, it is easier for Boron to lose an electron compared to Beryllium.

5. **Comparison**:
- Since Boron has a greater nuclear charge but a lower first ionization enthalpy compared to Beryllium, we conclude:
- **Boron has a greater nuclear charge than Beryllium.**
- **Beryllium has a greater first ionization enthalpy than Boron.**

6. **Final Answer**:
- In comparison to Boron (B), Beryllium (Be) has a **lower nuclear charge and a higher first ionization enthalpy**.