Atoms of which of the following have a valency equal to zero.

Options

A. Hydrogen
B. Nitrogen
C. Neon
D. Carbon

Explanation

To determine which atom has a valency equal to zero, we need to analyze the electronic configurations and valence electrons of the given atoms: Hydrogen, Nitrogen, Neon, and Carbon.

### Step-by-Step Solution:

1. **Identify the Atoms**: The atoms we are considering are Hydrogen (H), Nitrogen (N), Neon (Ne), and Carbon (C).

2. **Determine the Number of Electrons**:
- Hydrogen has 1 electron.
- Nitrogen has 7 electrons.
- Neon has 10 electrons.
- Carbon has 6 electrons.

3. **Write the Electronic Configuration**:
- For Hydrogen (1 electron): K shell → 1
- For Nitrogen (7 electrons): K shell → 2, L shell → 5
- For Neon (10 electrons): K shell → 2, L shell → 8
- For Carbon (6 electrons): K shell → 2, L shell → 4

4. **Identify Valence Electrons**:
- Valence electrons are the electrons in the outermost shell (valence shell).
- Hydrogen has 1 valence electron.
- Nitrogen has 5 valence electrons (in L shell).
- Neon has 8 valence electrons (in L shell).
- Carbon has 4 valence electrons (in L shell).

5. **Determine Valency**:
- The valency is determined based on the number of valence electrons:
- If valence electrons are less than 4, valency = number of valence electrons.
- If valence electrons are 4, valency = 4.
- If valence electrons are more than 4, valency = 8 - number of valence electrons.
- For Hydrogen: 1 valence electron → Valency = 1
- For Nitrogen: 5 valence electrons → Valency = 8 - 5 = 3
- For Neon: 8 valence electrons → Valency = 8 - 8 = 0
- For Carbon: 4 valence electrons → Valency = 4

6. **Conclusion**:
- The atom with a valency equal to zero is Neon (Ne).

### Final Answer:
The atom with a valency equal to zero is **Neon (Ne)**.