How did quantum mechanics change our understanding of atoms compared to classical physics?

• A. It showed that atoms are indivisible and cannot be broken down into smaller particles.
• B. It introduced the concept that electrons occupy specific energy levels and their positions are described by probability distributions rather than fixed orbits.
• C. It proved that electrons move in circular orbits around the nucleus, as described by the Bohr model.
• D. It demonstrated that atoms do not contain a nucleus and are made only of electrons.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the classical physics model of the atom, which described electrons as particles moving in fixed, circular orbits around the nucleus, similar to planets orbiting the sun.
2. Step 2: Recognize the limitations of the classical model, such as its inability to explain atomic spectra and the stability of atoms.
3. Step 3: Introduce quantum mechanics, which replaced fixed orbits with the concept of quantized energy levels where electrons can exist only at certain allowed energies.
4. Step 4: Learn that quantum mechanics describes electrons not as particles in precise paths but as wavefunctions, which give probability distributions for finding an electron in a particular region around the nucleus.
5. Step 5: Conclude that this probabilistic model fundamentally changed our understanding of atomic structure by showing that electron positions are inherently uncertain and defined by probabilities rather than exact trajectories.