The density of-

Options

A. `Na gt K`
B. `Na = K`
C. `K gt Na`
D. `Li gt K`

Answer

To solve the question regarding the density of sodium and potassium, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understand the Concept of Density**:
- Density is defined as mass per unit volume (Density = Mass/Volume). This means that for a given mass, if the volume increases, the density decreases, and vice versa.

**Hint**: Remember that density is a ratio of mass to volume.

2. **Compare the Mass of Sodium and Potassium**:
- Sodium (Na) has a lower atomic mass compared to potassium (K). However, we need to consider how this affects density in conjunction with volume.

**Hint**: Look up the atomic masses of sodium and potassium to see the difference.

3. **Consider the Role of d-Orbitals**:
- Potassium has d-orbitals that are not present in sodium. The presence of these d-orbitals contributes to an increase in the volume of potassium compared to sodium.

**Hint**: Reflect on how the presence of d-orbitals can influence the atomic structure and volume.

4. **Analyze the Volume of Sodium and Potassium**:
- Since potassium has a larger volume due to its electronic structure (d-orbitals), this means that even though potassium has a higher mass, its density will be affected by its larger volume.

**Hint**: Think about how an increase in volume affects density when mass is relatively higher.

5. **Conclusion on Density Comparison**:
- Given that density is inversely proportional to volume, and potassium has a larger volume than sodium, we conclude that the density of sodium is greater than that of potassium.

**Hint**: Summarize the relationship between mass, volume, and density to reinforce your conclusion.

### Final Answer:
The density of sodium is greater than that of potassium.