1. 3.2 Bohr’s Model of the Atom

2. PROBLEMS WITH THE RUTHERFORD MODEL
According to this model, an orbiting electron should continuously emit electromagnetic radiation and lose energy. This would cause it to collapse towards the nucleus since it is attracted to the (+) charge. This does not happen… WE NEED A NEW MODEL!

3. ATOMIC SPECTRUM OF THE HYDROGEN ATOM

4. EMISSION SPECTRUM – the spectrum of EMR emitted by an atom
EMISSION SPECTRUM – the spectrum of EMR emitted by an atom. There are two types…
1) CONTINUOUS SPECTRUM – an emission spectrum that contains all the wavelengths in a specific region of the electromagnetic spectrum

5. 2) LINE SPECTRUM – an emission spectrum that contains only those wavelengths characteristic of the element being studied.

6. Each element has its own unique line spectrum, like a fingerprint
Each element has its own unique line spectrum, like a fingerprint. New spectra = discovery of new element! Application in astronomy.

7. THE BOHR MODEL OF THE ATOM (consistent with line spectrum observations)
Electrons can only move in specific orbits around the nucleus
Each orbit corresponds to a state of constant (quantized) energy
Farther from the nucleus = higher energy level
If an electron got excited (gained more energy) it could move farther from the nucleus

9. BALL – STAIRCASE ANALOGY
The ball (electron) can only ever be found on a stair (orbit), so can only ever be a specific distance from the ground (nucleus). The higher the ball, the more potential energy it has.

10. The movement of an electron from one energy level to another is called a TRANSITION.
Transition to higher energy level … Electron absorbs energy (ex. is struck by a photon)
Transition to lower energy level … Electron emits a photon (or quantity of energy) GROUND STATE?