Which one is not in agreement with Bohr's model of the atom?

Options

A. (a) Line spectra of hydrogen atom
B. (b) Pauli's exclusion principle
C. (c) Planck's theory
D. (d) Heisenberg's uncertainty principle

Answer

To determine which statement is not in agreement with Bohr's model of the atom, we need to analyze the options provided in the context of Bohr's postulates.

### Step-by-Step Solution:

1. **Understanding Bohr's Model**:
- Bohr's model states that electrons revolve around the nucleus in fixed, stable orbits. Each orbit corresponds to a specific energy level, and the angular momentum of an electron in these orbits is quantized, given by the formula \( L = n \frac{h}{2\pi} \), where \( n \) is a positive integer and \( h \) is Planck's constant.

**Hint**: Recall the key postulates of Bohr's model, especially regarding electron orbits and angular momentum.

2. **Evaluating the Options**:
- **Option A: Line spectra of hydrogen atom**:
- Bohr's model successfully explains the line spectra of hydrogen by allowing electrons to transition between energy levels, emitting or absorbing photons in the process. This is in agreement with Bohr's model.

**Hint**: Consider how Bohr's model accounts for the emission and absorption of light by hydrogen.

- **Option B: Pauli's exclusion principle**:
- This principle states that no two electrons can have the same set of quantum numbers in an atom. While it applies to multi-electron atoms, it does not contradict Bohr's model, which primarily focuses on single-electron systems like hydrogen.

**Hint**: Think about how Pauli's principle relates to electron configurations and whether it conflicts with Bohr's model.

- **Option C: Planck's theory**:
- Bohr's model incorporates Planck's theory of quantization of energy. The quantization of angular momentum is based on Planck's constant, so this is also in agreement with Bohr's model.

**Hint**: Reflect on the relationship between Planck's theory and the quantization in Bohr's model.

- **Option D: Heisenberg's uncertainty principle**:
- This principle states that it is impossible to simultaneously know both the position and momentum of a particle with absolute certainty. This contradicts Bohr's model, which provides a definite value for the angular momentum of electrons in their orbits.

**Hint**: Consider how the uncertainty principle challenges the precise calculations made in Bohr's model.

3. **Conclusion**:
- The statement that is not in agreement with Bohr's model is **Option D: Heisenberg's uncertainty principle**. This principle contradicts Bohr's assertion of precise angular momentum values for electrons.

### Final Answer:
The option that is not in agreement with Bohr's model of the atom is **D: Heisenberg's uncertainty principle**.