All the elements, on the basis of long form of periodic table, can be divided into four blocks, s,p, d and f. the ionization energies, electron affinities, electronegativities, atomic and ionic radii and other physical properties usually shown a regular pattern of change within a group or along period with some irregularities.
Q. Which of the following element has the maximum electron affinity?

Options

A. Nitrogen
B. Oxygen
C. Fluorine
D. Chlorine

Answer

To determine which element has the maximum electron affinity among the given options (Nitrogen, Oxygen, Fluorine, and Chlorine), we can follow these steps:

### Step 1: Understand Electron Affinity
Electron affinity is defined as the amount of energy released when an electron is added to a neutral atom in the gaseous state. Higher electron affinity means that the atom more readily accepts an electron.

### Step 2: Analyze the Given Elements
The elements provided are:
- Nitrogen (N): Electronic configuration is \(1s^2 2s^2 2p^3\)
- Oxygen (O): Electronic configuration is \(1s^2 2s^2 2p^4\)
- Fluorine (F): Electronic configuration is \(1s^2 2s^2 2p^5\)
- Chlorine (Cl): Electronic configuration is \(1s^2 2s^2 2p^6 3s^2 3p^5\)

### Step 3: Determine the Need for Electrons
- Nitrogen needs 3 electrons to achieve a stable noble gas configuration (Neon).
- Oxygen needs 2 electrons to achieve a stable noble gas configuration (Neon).
- Fluorine needs 1 electron to achieve a stable noble gas configuration (Neon).
- Chlorine needs 1 electron to achieve a stable noble gas configuration (Argon).

### Step 4: Compare Electron Affinities
- Fluorine and Chlorine both need one electron to achieve noble gas configuration. However, they differ in their atomic sizes and electronegativities.
- Fluorine is the most electronegative element, but due to its small atomic size, it has a higher electron-electron repulsion when an electron is added, making its electron affinity slightly lower than that of Chlorine.
- Chlorine, being larger than Fluorine, has less electron-electron repulsion when gaining an electron, which allows it to have a higher electron affinity.

### Step 5: Conclusion
Based on the analysis, Chlorine has the maximum electron affinity among the given elements.

### Final Answer
The element with the maximum electron affinity is **Chlorine (Cl)**.

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