Background
A Danish physician born in 1885 and died 1962.
Studied under Thompson. § Received the Nobel Prize in Physics for his work on the atomic structure. § Served as an advisor to the scientists in Los Namos, New Mexico, who were working on the atomic bomb. § Later devoted much of his time to promoting peaceful uses of nuclear energy, receiving the first Atoms for Peace award in 1957. Experiments § Made numerous contributions to the study of the nucleus of the atom, and the understanding of quantum mechanics during the 1930s. § Bohr, aided by the theory proposed by Max Planck, described the way atoms emit radiation. § Bohr assumed that when an electron jumps from an outer orbit to an inner orbit, it emits light. Theory § His model was based on Rutherford’s theory. § Bohr proposed that Rutherford’s electrons could only travel in certain successively larger orbits around the nucleus. § He thought the outer orbits could hold more electrons than the inner orbits. § He also suggested that the electrons in the outer most orbits determined the chemical properties of the atom. § His theory of the electron emitting light as it jumps from an outer orbit to an inner orbit, explained the way light is given off by hydrogen, the simplest atom. § Bohr proposed that an electron could jump suddenly between these orbits by absorbing or emitting a photon with the appropriate wavelength § According to classical physics, an electron in orbit around an atomic nucleus should emit electromagnetic radiation continuously, because it is continuously accelerating in a curved path. The resulting loss of energy implies that the electron should spiral into the nucleus in a very short time. § Bohr used quantum theory to explain why electrons could remain in certain allowed orbits without radiating energy.
A diagram of Bohr's Atom Model theory.
Bohr Quantum Hypothesis where v is the velocity of an electron and r its orbital radius
Simplified version of Bohr's Atom Theory, with the electrons in orbits around the nucleus.
