In graphite, electrons are

Options

A. Localised on each carbon-atom
B. Localised on every third C-atom
C. Delocalised within the layer
D. Present in anti-bonding orbital

Answer

To solve the question regarding the behavior of electrons in graphite, we will analyze the structure of graphite and the nature of the bonding within it.

### Step-by-Step Solution:

1. **Understanding the Structure of Graphite**:
- Graphite has a layered structure where carbon atoms are arranged in hexagonal lattices. Each layer consists of carbon atoms bonded to three other carbon atoms.

**Hint**: Visualize the structure of graphite as layers of hexagons, similar to a honeycomb.

2. **Hybridization of Carbon Atoms**:
- In graphite, each carbon atom undergoes sp² hybridization. This means that one s orbital and two p orbitals mix to form three sp² hybrid orbitals.

**Hint**: Recall that sp² hybridization involves one s and two p orbitals, leading to three equivalent orbitals.

3. **Bonding in Graphite**:
- Each carbon atom forms three sigma (σ) bonds with three neighboring carbon atoms using the sp² hybrid orbitals. The remaining p orbital on each carbon atom is unhybridized.

**Hint**: Remember that sigma bonds are formed through head-on overlapping of orbitals.

4. **Delocalization of Electrons**:
- The unhybridized p orbitals of adjacent carbon atoms overlap, allowing electrons to be delocalized across the entire layer. This delocalization is what gives graphite its electrical conductivity.

**Hint**: Think of delocalized electrons as being free to move within the layer, contributing to conductivity.

5. **Evaluating the Options**:
- **Option A**: Localized in each carbon atom - Incorrect, as electrons are not confined to individual atoms.
- **Option B**: Localized in every third carbon atom - Incorrect, as electrons are not restricted to every third atom.
- **Option C**: Localized within a layer - Correct, as the delocalized electrons are spread across the layer.
- **Option D**: Present in anti-bonding orbitals - Incorrect, as the electrons are not in anti-bonding orbitals.

**Hint**: Analyze each option based on the understanding of electron behavior in the structure of graphite.

6. **Conclusion**:
- The correct answer is **C: localized within a layer**, as the electrons in graphite are delocalized across the layers, contributing to its properties.

### Final Answer:
The correct option is **C: localized within a layer**.