Which statement describes the Bohr model?

• A. A model of the atom with a dense, positively charged nucleus and electrons in fixed orbits with discrete energy levels.
• B. A purely quantum mechanical description with electron clouds.
• C. A description of nucleons in a nucleus bound by the strong force.
• D. A classical model without quantized energy states.

Answer: (A)

The Bohr model pictures an atom as a tiny, dense nucleus with electrons moving in fixed, circular orbits around it, and only certain orbits being allowed because the energies are quantized. This combination of a central nucleus and discrete energy levels explains why atoms emit or absorb light in specific wavelengths: transitions occur between those allowed orbits, producing the characteristic spectral lines. It was introduced to explain hydrogen’s spectrum and to link the Rutherford picture of a nucleus with early quantum ideas. While modern quantum mechanics describes electrons as probability clouds or orbitals rather than exact paths, the Bohr idea of fixed, quantized orbits around a dense nucleus remains the classic description of the atom’s structure. Other descriptions refer to electron clouds, nuclear binding by the strong force, or a purely classical view without quantization, which do not fit the Bohr model.