Bohr's atomic model is applicable for

Options

A. Hydrogen atom only
B. Unielectron atomic system only
C. All atoms
D. All isotopes of hydrogen only

Answer

To determine for which systems Bohr's atomic model is applicable, we can analyze the options provided and the fundamental principles of the model.

### Step-by-Step Solution:

1. **Understanding Bohr's Model**:
- Bohr's atomic model was proposed to explain the behavior of electrons in atoms, specifically how they orbit the nucleus.
- The model is based on quantized energy levels, meaning that electrons can only occupy certain allowed orbits without radiating energy.

2. **Identifying the Electron Configuration**:
- Bohr's model is specifically designed for systems with a single electron. This is because the model simplifies the calculations and assumptions about electron interactions.

3. **Evaluating the Options**:
- **Option 1: Hydrogen Atom**:
- The hydrogen atom has one electron and is indeed a valid application of Bohr's model. However, it is not the only system where the model applies.
- **Option 2: Unielectronic Atomic Systems**:
- This option refers to any atomic system that has only one electron, such as hydrogen (H), singly ionized helium (He+), and other similar ions. This is the correct option because Bohr's model applies to all unielectronic systems.
- **Option 3: All Atoms**:
- This is incorrect because Bohr's model does not apply to multi-electron atoms due to the complexities of electron-electron interactions.
- **Option 4: All Isotopes of Hydrogen**:
- While isotopes of hydrogen (like deuterium and tritium) have one electron, the statement is too restrictive and does not encompass all unielectronic systems.

4. **Conclusion**:
- The correct answer is **Option 2: Unielectronic Atomic Systems**. Bohr's atomic model is applicable to any system that contains only one electron.