Q.State two major limitations of Bohr's model of the atom.

Bohr's model, despite correctly predicting the hydrogen spectrum, has several well-known limitations. Any two of the following may be given:

1. Fails for multi-electron atoms/ions. The model works only for one-electron species (H, $\text{He}^+$, $\text{Li}^{2+}$, …). It cannot correctly predict the spectrum of any atom or ion with two or more electrons, because it does not account for electron-electron repulsion.

2. Cannot explain fine structure. When hydrogen's spectral lines are examined at high resolution, each line is actually found to be a closely spaced group of several lines (fine structure) -- Bohr's model, which allows only a single, sharp energy for each orbit, cannot account for this splitting.

3. Cannot explain the Zeeman and Stark effects. Spectral lines are observed to split further when the atom is placed in an external magnetic field (Zeeman effect) or electric field (Stark effect); Bohr's model has no mechanism to produce this.

4. Cannot explain directional bonding. It gives no explanation for why atoms combine to form molecules with specific bond angles and directional character.

5. Violates the uncertainty principle. It assumes the electron moves in a precisely defined circular path with an exactly known position and velocity at every instant, which directly contradicts Heisenberg's uncertainty principle.

Recall the standard, well-documented shortcomings of Bohr's model and select any two with a brief explanation of each.

Stating only that 'it is wrong' without naming a specific, concrete phenomenon it fails to explain.