Increasing order of Electron affinity for following configuration.
(a) `1s^(2),2s^(2),2p^(2)` (b) `1s^(2), 2s^(2) 2p^(4)`
(c) `1s^(2), 2s^(2), 2p^(6),3s^(2), 3p^(4)` (d) `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(3)`

Options

A. d `lt` a`lt` b `lt` c
B. d `lt` a `lt` c `lt` b
C. a `lt` b `lt` c `lt` d
D. a `lt` b `lt` d `lt` c

Answer

To determine the increasing order of electron affinity for the given electron configurations, we first need to identify the elements corresponding to each configuration and then analyze their electron affinities based on their positions in the periodic table.

### Step-by-Step Solution:

1. **Identify the Elements**:
- (a) `1s^(2), 2s^(2), 2p^(2)` corresponds to Carbon (C), atomic number 6.
- (b) `1s^(2), 2s^(2), 2p^(4)` corresponds to Oxygen (O), atomic number 8.
- (c) `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(4)` corresponds to Sulfur (S), atomic number 16.
- (d) `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(3)` corresponds to Phosphorus (P), atomic number 15.

2. **Understanding Electron Affinity**:
- Electron affinity is the amount of energy released when an electron is added to a neutral atom. Generally, as we move across a period from left to right, electron affinity increases due to increased nuclear charge attracting the added electron more strongly.
- However, there are exceptions due to electron-electron repulsions, particularly in small atoms like Oxygen.

3. **Comparing Electron Affinities**:
- **Carbon (C)**: Has a moderate electron affinity.
- **Oxygen (O)**: Although it is a small atom, the high electron-electron repulsion in its already filled p-orbitals leads to a lower electron affinity compared to what might be expected.
- **Phosphorus (P)**: Has a lower electron affinity than Sulfur due to being in the same group but having a larger atomic size.
- **Sulfur (S)**: Has a higher electron affinity than Oxygen because the size is larger, reducing the repulsion effect when an electron is added.

4. **Order of Electron Affinity**:
- Based on the above analysis, the order from lowest to highest electron affinity is:
- (b) Oxygen (O) < (c) Sulfur (S) < (d) Phosphorus (P) < (a) Carbon (C)

5. **Final Increasing Order**:
- Therefore, the increasing order of electron affinity for the given configurations is:
- (b) < (c) < (d) < (a)

### Summary of Increasing Order:
- (b) `1s^(2), 2s^(2), 2p^(4)` (Oxygen) <
- (c) `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(4)` (Sulfur) <
- (d) `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(3)` (Phosphorus) <
- (a) `1s^(2), 2s^(2), 2p^(2)` (Carbon)