sourced story
1913 CEPrimary source · 2 sourcesWell documented

Bohr Proposes a Quantized Model of the Atom

Electrons are only allowed to orbit at certain distances, and this alone explains hydrogen's light

On the timeline · around 1913 CE · The Quantum and Relativity RevolutionClassical PhysicsThe Quantum and Relativity RevolutionBohr Proposes a Quantized Model of the Atom189019051910191519201925

Quick facts

Published
1913, three papers on atomic structure
Core idea
Electrons occupy fixed, quantized orbits
Explained
Hydrogen's spectral lines
Later status
Superseded by full quantum mechanics, 1925-1926

What happened

In 1913 the Danish physicist Niels Bohr wrote a paper on the hydrogen atom that broke with classical theory, the first of three papers that year, discovering the major laws governing hydrogen's spectral lines, the specific colors of light hydrogen atoms absorb and emit. Bohr's model combined aspects of classical physics with Max Planck's concept of the quantum of action: electrons could only occupy certain fixed orbits around the nucleus, each with a specific quantized energy, and light was emitted or absorbed only when an electron jumped between these fixed orbits. The model successfully predicted the exact wavelengths of hydrogen's spectral lines, a result classical physics could not explain at all.

Why it matters

Bohr's atom was, in MacTutor's words, not immediately accepted by everyone, but it intrigued his contemporaries and made them aware of the need for a new way of describing events at the atomic level. Though later superseded by the full quantum mechanics of Heisenberg and Schrodinger, the Bohr model remains, as MacTutor notes, a vivid image of what atoms look like and a symbol of physics in the popular imagination, and it was the first successful bridge between Planck's quantum idea and the structure of the atom itself.

How we know

Bohr's three 1913 papers were published in Philosophical Magazine and form the direct documentary basis for MacTutor's account of his early reputation; the model's spectral-line predictions were independently verified by comparison to existing precise measurements of the hydrogen spectrum.

Sources

See something wrong? . Corrections with a source get fixed fastest.

Part of a timelineHistory of Physics24 events · A search for the rules the universe obeys, from falling stones and floating crowns to a boson found underground and ripples in spacetimeView all →
Bohr Proposes a Quantized Model of the Atom · History of Physics · SourcedStory