If the magnetic of the atom of a substance is zero the substance is called

Options

A. diamagnetic
B. paramagnetie
C. antiferromagnetic
D. ferromagnetic

Answer

To determine what a substance is called when the magnetic moment of its atoms is zero, we can analyze the properties of different types of magnetic materials.

### Step-by-Step Solution:

1. **Understand Magnetic Properties**:
- There are different types of magnetic materials: diamagnetic, paramagnetic, antiferromagnetic, and ferromagnetic. Each has distinct behaviors in the presence of an external magnetic field.

2. **Diamagnetic Materials**:
- Diamagnetic materials have no unpaired electrons, which means they do not have a net magnetic moment. When placed in an external magnetic field, they do not align with the field and thus exhibit a magnetic moment of zero.

3. **Paramagnetic Materials**:
- Paramagnetic materials have unpaired electrons and will align with an external magnetic field, resulting in a non-zero magnetic moment. Therefore, they cannot be the answer.

4. **Antiferromagnetic Materials**:
- Antiferromagnetic materials have atoms that align in opposite directions in the presence of an external magnetic field, resulting in a net magnetic moment that is also non-zero.

5. **Ferromagnetic Materials**:
- Ferromagnetic materials have atoms that align parallel to each other in the presence of an external magnetic field, leading to a strong net magnetic moment, which is also non-zero.

6. **Conclusion**:
- Since diamagnetic materials are the only type that exhibit zero magnetic moment, the correct answer is that if the magnetic moment of the atom of a substance is zero, the substance is called **diamagnetic**.

### Final Answer:
The substance is called **diamagnetic**.