Atoms

Electrons revolve in stable orbits without radiating energy, Angular momentum is quantized as L = nh/2π, Photon energy equals energy difference between initial and final states

Bohr's three postulates state: (1) electrons revolve in stable orbits without emission, (2) angular momentum is quantized as L = nh/2π, and (3) photon energy equals the energy difference between states. Energy is absorbed when jumping to higher orbits, not emitted.

Line emission spectrum

Excited atomic gases at low pressure emit line emission spectra, consisting of bright lines on a dark background at specific wavelengths characteristic of the element.

The energy level of the electron

The principal quantum number n determines the energy level and orbital radius of the electron in Bohr's model, with n = 1, 2, 3... representing different allowed energy states.

Cannot explain atomic stability, Cannot explain line spectra, Predicts continuous spectrum instead of line spectrum

Rutherford's model fails to explain why atoms are stable (accelerating electrons should spiral into nucleus) and why atoms emit line spectra instead of continuous spectra. However, it successfully explains the nuclear structure and alpha particle scattering.