Bohr model
![The Rutherford–Bohr model of the hydrogen atom (Z = 1) or a hydrogen-like ion (Z > 1), where the negatively charged electron confined to an atomic shell encircles a small, positively charged atomic nucleus and where an electron jump between orbits is accompanied by an emitted or absorbed amount of electromagnetic energy (hν).[1] The orbits in which the electron may travel are shown as grey circles; their radius increases as n2, where n is the principal quantum number. The 3 → 2 transition depicted here produces the first line of the Balmer series, and for hydrogen (Z = 1) it results in a photon of wavelength 656 nm (red light).](/Images/godic/202501/01/Bohr-atom-PAR.svg0007.png")
![Bohr model showing maximum electrons per shell with shells labeled in X-ray notation](/Images/godic/202501/01/Atome_bohr_couches_electroniques_KLM.svg0007.png")
![Models depicting electron energy levels in hydrogen, helium, lithium, and neon](/Images/godic/202501/01/Blausen_0342_ElectronEnergyLevels0007.png")
![Elliptical orbits with the same energy and quantized angular momentum](/Images/godic/202501/01/Sommerfeld_ellipses.svg0007.png")
In atomic physics, the Rutherford–Bohr model or Bohr model, introduced by Niels Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with attraction provided by electrostatic forces rather than gravity. After the cubic model (1902), the plum-pudding model (1904), the Saturnian model (1904), and the Rutherford model (1911) came the Rutherford–Bohr model or just Bohr model for short (1913). The improvement to the Rutherford model is mostly a quantum physical interpretation of it. The Bohr model has been superseded, but the quantum theory remains sound.