Which of the following are correct

Options

A. `IE_(2)(Mg)ltIE_(2)(Na)`
B. `EA(N)ltEA(P)`
C. Atomic size `Mg^(+2)gt` Atomic size `(Li^(+))`
D. IP of Na `lt` Mg `lt` Al

Answer

To determine which statements regarding ionization enthalpy, electron affinity, atomic size, and ionization potential are correct, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Ionization Enthalpy**:
- Ionization enthalpy (or ionization energy) is the energy required to remove an electron from an atom in the gaseous state.
- For sodium (Na), the electronic configuration is [Ne] 3s¹, while for magnesium (Mg), it is [Ne] 3s².

2. **First Ionization Energy**:
- When we remove one electron from sodium, it becomes Na⁺ ([Ne]), while removing one electron from magnesium gives Mg⁺ ([Ne] 3s¹).
- The first ionization energy of magnesium is higher than that of sodium because magnesium has a more stable electronic configuration after losing one electron.

3. **Second Ionization Energy**:
- For the second ionization energy, removing another electron from Na⁺ results in a stable noble gas configuration (Ne), while removing an electron from Mg⁺ leads to a less stable configuration (3s¹).
- Therefore, the second ionization energy of magnesium is higher than that of sodium. This makes the first statement correct.

4. **Electron Affinity**:
- Electron affinity is the energy change when an electron is added to an atom.
- Phosphorus (P) and nitrogen (N) are in the same group, but phosphorus has a larger atomic radius than nitrogen.
- As atomic size increases, the electron affinity generally decreases due to increased distance from the nucleus.
- Therefore, the statement regarding electron affinity (that it decreases from nitrogen to phosphorus) is correct, making the second statement incorrect.

5. **Atomic Size of Ions**:
- The size of ions is affected by their charge. A higher positive charge results in a smaller ionic radius.
- Lithium ion (Li⁺) has a +1 charge, while magnesium ion (Mg²⁺) has a +2 charge.
- Thus, Mg²⁺ is smaller than Li⁺, making the statement about their sizes incorrect.

6. **Ionization Potential**:
- Ionization potential is equivalent to ionization energy.
- The order of ionization potential based on electronic configuration is generally: Mg > Na > Al.
- Magnesium has a full outer shell (3s²), making it more stable and requiring more energy to remove an electron compared to sodium and aluminum.
- Therefore, the statement regarding ionization potential is incorrect.

### Conclusion:
- The only correct statement is regarding the second ionization enthalpy of magnesium being higher than that of sodium.

### Final Answer:
- The correct option is the first statement.