Spectroscopy

C) Limitations of Bohr Model

1) electron couldn’t circle around nucleus like a planet! …

Because they would lose energy (by emitting electromagnetic radiation) & spiral into nucleus.

2) Bohr was not able to explain electron orbits of large atom w/ many electrons

Uncertainty Principle

Deutsches Bundesarchiv (German Federal Archive), Bild183-R57262

Werner Heisenberg

When you are studying sub-atomic particles, you change them.

(A particles position and momentum are affected by your measuring devices.)

You can be certain about the position or momentum of a subatomic particle but never both
at the same time.

The more know about the momentum of a subatomic particle, the less you know about its position and vice versa

Present Theory of the Atom
Cloud Model

Electrons do not have precisely described positions and momenta

The 'probable' position and momenta are described mathematically

Electrons occupy regions in space called 'clouds'.

Spectral Lines - Electron Cloud Model

Enrichment

What are stars made of ?

Spectroscope