How does the current quantum mechanical model of the atom differ from the Bohr model?

• A. The quantum mechanical model restricts electrons to specific energy levels without any probability interpretation.
• B. Both models treat electrons as particles with definite positions at all times.
• C. The Bohr model allows for electron clouds, while the quantum mechanical model uses fixed paths.
• D. The quantum mechanical model describes electron positions as probability distributions (orbitals), while the Bohr model assigns electrons to fixed circular orbits.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the Bohr model of the atom, which describes electrons as particles moving in fixed, circular orbits around the nucleus with quantized energy levels.
2. Step 2: Recognize that the Bohr model treats electrons as having definite positions and paths, similar to planets orbiting the sun, without accounting for the wave-like nature of electrons.
3. Step 3: Learn that the quantum mechanical model replaces fixed orbits with orbitals, which are regions in space where there is a high probability of finding an electron, reflecting the wave-particle duality of electrons.
4. Step 4: Note that the quantum mechanical model uses probability distributions to describe electron positions, meaning electrons do not have exact paths but rather exist in 'clouds' of probability.
5. Step 5: Summarize the key difference: the Bohr model assigns electrons to fixed circular orbits, while the quantum mechanical model describes electrons as existing in orbitals defined by probability distributions.