The correct order of second I.P.

Options

A. Na`lt` Mg `gt` Al`lt` Si
B. Na`gt` Mg `lt` Al`gt` Si
C. Na`gt` Mg`gt` Al`lt` Si
D. Na`gt` Mg`gt` Al`gt` Si

Answer

To determine the correct order of the second ionization potential (I.P.) for sodium (Na), magnesium (Mg), aluminum (Al), and silicon (Si), we can follow these steps:

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

### Step 2: Write Electronic Configurations
Identify the electronic configurations of the elements:
- Sodium (Na): 1s² 2s² 2p⁶ 3s¹
- Magnesium (Mg): 1s² 2s² 2p⁶ 3s²
- Aluminum (Al): 1s² 2s² 2p⁶ 3s² 3p¹
- Silicon (Si): 1s² 2s² 2p⁶ 3s² 3p²

### Step 3: Consider the First Ionization
For the first ionization, each element loses one electron:
- Na → 1s² 2s² 2p⁶ (Na⁺)
- Mg → 1s² 2s² 2p⁶ 3s¹ (Mg⁺)
- Al → 1s² 2s² 2p⁶ 3s² 3p⁰ (Al²⁺)
- Si → 1s² 2s² 2p⁶ 3s² 3p¹ (Si⁺)

### Step 4: Analyze the Stability of Ions
After the first ionization:
- Na⁺ has a stable noble gas configuration (1s² 2s² 2p⁶).
- Mg⁺ has a stable noble gas configuration (1s² 2s² 2p⁶).
- Al²⁺ has a partially filled configuration, which is less stable than the filled configurations.
- Si⁺ also has a partially filled configuration.

### Step 5: Determine the Second Ionization Energy
The second ionization energy will be influenced by the stability of the resulting ions:
- Na has a stable noble gas configuration after losing one electron, so removing another electron requires a lot of energy.
- Mg also has a stable noble gas configuration after losing one electron, but it has a full outer shell, making it more stable than Al²⁺ and Si⁺.
- Al²⁺ and Si⁺ are less stable due to their partially filled configurations.

### Step 6: Order the Second Ionization Potentials
Based on the stability of the resulting ions after the first ionization:
1. Na (highest second I.P. due to stability of Na⁺)
2. Mg (next highest due to stability of Mg⁺)
3. Al (lower due to less stability of Al²⁺)
4. Si (lowest due to less stability of Si⁺)

### Final Order of Second Ionization Potential
The correct order of second ionization potential is:
**Na > Mg > Al > Si**