which is the same for graphite and diamond:

Options

A. atomic weight
B. crystalline structure
C. density
D. electrical conductivity

Answer

To determine which property is the same for graphite and diamond, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding the Allotropes**:
- Graphite and diamond are two different allotropes of carbon. This means they are different structural forms of the same element, carbon.

2. **Analyzing the Options**:
- **Option A: Atomic Weight**:
- Both graphite and diamond are composed of carbon atoms. The atomic weight of carbon is 12 atomic mass units (A.M.U). Therefore, the atomic weight is the same for both.

- **Option B: Crystalline Structure**:
- Graphite has a layered structure, where carbon atoms are arranged in sheets. In contrast, diamond has a three-dimensional tetrahedral structure. Hence, their crystalline structures are different.

- **Option C: Density**:
- The density of graphite is approximately 2.26 grams per cubic centimeter (g/cm³), while the density of diamond is about 3.52 g/cm³. Therefore, their densities are not the same.

- **Option D: Electrical Conductivity**:
- Graphite is a good conductor of electricity due to the mobility of electrons in its layered structure. On the other hand, diamond is a poor conductor of electricity because it has no free electrons. Thus, their electrical conductivities are also different.

3. **Conclusion**:
- The only property that is the same for both graphite and diamond is their atomic weight, which is 12 A.M.U.

### Final Answer:
**The same for graphite and diamond is: A) Atomic Weight.**