In the ground state in ...A... electrons are in stable equilibrium while in ...B... electrons always experiences a net force. Here, A and B refer to

Options

A. Dalton's theory, Rutherford model
B. Rutherford's model, Bohr's model
C. Thomson's model, Rutherford's model
D. Rutherford's model, Thomson's model

Explanation

To solve the question, we need to identify the models of atomic structure referred to as A and B based on the behavior of electrons in their ground states.

### Step-by-Step Solution:

1. **Understanding the Ground State**:
- The ground state of an atom is the lowest energy state where electrons are in stable positions around the nucleus.

2. **Identifying Model A**:
- In Model A, electrons are in stable equilibrium. This indicates that the forces acting on the electrons balance out, leading to a stable configuration.
- The Thomson model of the atom, also known as the "plum pudding model," suggests that electrons are embedded in a positively charged "soup," allowing them to remain stable without experiencing a net force.

3. **Identifying Model B**:
- In Model B, electrons experience a net force. This suggests that the electrons are not in a stable equilibrium and are subject to forces that cause them to accelerate.
- The Rutherford model describes electrons moving in orbits around a nucleus, where they are subject to centripetal force. This model indicates that electrons would spiral into the nucleus due to the attractive force, leading to instability.

4. **Conclusion**:
- Therefore, based on the descriptions:
- Model A refers to **Thomson's model** (where electrons are in stable equilibrium).
- Model B refers to **Rutherford's model** (where electrons experience a net force and are unstable).

### Final Answer:
A refers to Thomson's model, and B refers to Rutherford's model.

---