Atomic Structure Timeline

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Niels Bohr (1913)

Bright-Line Spectrum

tried to explain presence of specific colors in hydrogen’s spectrum

Energy Levels

electrons can only exist in specific energy states

Planetary Model

Slide 12

Niels Bohr (1913)

Planetary Model

electrons move in circular orbits within specific energy levels

Bright-line spectrum

Slide 13

Erwin Schrödinger (1926)

Quantum mechanics

electrons can only exist in specified energy states

Electron cloud model

orbital: region around the nucleus where e- are likely to be found

Slide 14

Erwin Schrödinger (1926)

Electron Cloud Model (orbital)

dots represent probability of finding an e- not actual electrons

Slide 15

James Chadwick (1932)

Discovered neutrons

neutral particles in the nucleus of an atom

Joliot-Curie Experiments

based his theory on their experimental evidence

Slide 16

James Chadwick (1932)

Neutron Model

revision of Rutherford’s Nuclear Model