The element which has highest `II^(nd)` I.E. ?

Options

A. Li
B. Be
C. K
D. B

Answer

To determine the element with the highest second ionization energy (I.E. II), we need to analyze the ionization energies of the given elements. Here’s a step-by-step solution:

### Step 1: Understand Ionization Energy
Ionization energy is the energy required to remove an electron from a gaseous atom. The second ionization energy refers to the energy required to remove a second electron after the first has already been removed.

### Step 2: Analyze the Given Elements
We will consider the following elements based on their atomic numbers and electronic configurations:
1. **Lithium (Li)** - Atomic number 3; Electronic configuration: 1s² 2s¹ (2, 1)
2. **Beryllium (Be)** - Atomic number 4; Electronic configuration: 1s² 2s² (2, 2)
3. **Potassium (K)** - Atomic number 19; Electronic configuration: 1s² 2s² 2p⁶ 3s¹ (2, 8, 8, 1)
4. **Boron (B)** - Atomic number 5; Electronic configuration: 1s² 2s² 2p¹ (2, 3)

### Step 3: Determine the First Ionization Energy
- **For Lithium (Li)**: Removing the first electron gives a configuration of 1s² (noble gas configuration of Helium). The second ionization energy will be high because removing an electron from a noble gas configuration requires a lot of energy.
- **For Beryllium (Be)**: Removing the first electron gives a configuration of 1s² 2s¹. The second ionization energy will be lower than that of Li because the resulting configuration (1s²) is stable but not a noble gas configuration.
- **For Potassium (K)**: Removing the first electron gives a configuration of 1s² 2s² 2p⁶ (noble gas configuration of Argon). The second ionization energy will be high, but still lower than that of Li.
- **For Boron (B)**: Removing the first electron gives a configuration of 1s² 2s². The second ionization energy will be lower than that of Li and Be as the resulting configuration is not stable.

### Step 4: Compare the Second Ionization Energies
- **Li**: After the first removal, it achieves a noble gas configuration (He), making the second ionization energy very high.
- **Be**: The second ionization energy will be lower than Li because the resulting configuration is not a noble gas.
- **K**: The second ionization energy will be lower than Li but higher than Be.
- **B**: The second ionization energy will be the lowest among these options.

### Step 5: Conclusion
After analyzing the ionization energies, we can conclude that Lithium (Li) has the highest second ionization energy due to its stable noble gas configuration after the removal of the first electron.

### Final Answer
The element with the highest second ionization energy is **Lithium (Li)**.

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