Which one of the following elements of period 2 has high electron affinity?

Options

A. Lithium
B. Carbon
C. Fluorine
D. Neon

Answer

To determine which element of period 2 has the highest electron affinity, 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 gaseous atom. This process results in the formation of an anion.

**Hint:** Remember that electron affinity is about how much an atom "wants" to gain an electron.

### Step 2: Identify the Elements in Period 2
The elements in period 2 of the periodic table are:
- Lithium (Li)
- Beryllium (Be)
- Boron (B)
- Carbon (C)
- Nitrogen (N)
- Oxygen (O)
- Fluorine (F)
- Neon (Ne)

**Hint:** List all the elements in the period to visualize your options.

### Step 3: Recognize the Trend in Electron Affinity
The trend in electron affinity generally increases as you move from left to right across a period. This means that elements on the right side of the periodic table tend to have higher electron affinities compared to those on the left.

**Hint:** Think about how the atomic structure changes across the period and how that affects electron affinity.

### Step 4: Analyze Specific Elements
- **Beryllium (Be)** has a completely filled valence shell (1s² 2s²), which results in a very low electron affinity because it does not favor gaining an electron.
- **Neon (Ne)** also has a completely filled valence shell (1s² 2s² 2p⁶), leading to a very low electron affinity.
- **Nitrogen (N)** has a half-filled p orbital (1s² 2s² 2p³), which is relatively stable and results in lower electron affinity compared to elements like oxygen and fluorine.
- **Oxygen (O)** has a higher electron affinity than nitrogen due to its higher effective nuclear charge and desire to complete its p orbital.
- **Fluorine (F)** has the highest electron affinity in period 2 because it is one electron away from a stable noble gas configuration.

**Hint:** Compare the electronic configurations and stability of each element to assess their electron affinity.

### Step 5: Conclusion
Based on the trends and analysis, **Fluorine (F)** has the highest electron affinity among the elements in period 2.

**Final Answer:** Fluorine (F) has the highest electron affinity in period 2.