1. 5.1
Light & Energy
F. Electrons & Light
Bohr’s Model of the Atom: Electrons orbit the nucleus in fixed orbits around the nucleus.
Light (EM radiation): Caused when excited electrons “jump” from one energy level (orbital) and then return to original energy level (orbital)

2. F. Electrons & Light ) ) ) ) ) ) ) 1 2 3 4 5 6 7 energy levels
5.1
Light & Energy
F. Electrons & Light
As energy is absorbed, electrons move from their ground state (original energy level) to an excited state (higher energy level)
energy levels
Initial position
Final position
) ) ) ) ) ) )
nucleus
excited state
ground state

3. F. Electrons & Light ) ) ) ) ) ) ) 1 2 3 4 5 6 7 energy levels
5.1
Light & Energy
F. Electrons & Light
Electrons are unstable in their excited state, so they return to the ground state by releasing energy. During this return, light is emitted!
energy levels
Final position
Initial position
) ) ) ) ) ) )
nucleus
excited state
ground state

4. G. Atomic Emission Spectra
A prism separates light into the colors it contains. When white light passes through a prism, it produces a rainbow of colors.
A prism separates light into the colors it contains. For white light this produces a rainbow of colors.

5. G. Atomic Emission Spectra
5.1
When light from a helium lamp passes through a prism, discrete lines are produced.
A prism separates light into the colors it contains. Light from a helium lamp produces discrete lines. Identifying Which color has the highest frequency?

6. G. Atomic Emission Spectra
5.1
G. Atomic Emission Spectra
The set of frequencies of light emitted by an element separate into discrete lines to give the atomic spectrum of the element.
Mercury
Nitrogen
No two elements have the same emission spectrum. a) Mercury vapor lamps produce a blue glow. b) Nitrogen gas gives off a yellowish-orange light.

7. H. Spectra of Light
Each element has its own unique atomic emission spectrum. Like a “fingerprint” for that element.

8. H. Spectra of Light
We see different colors of light (wavelengths) depending on how many energy levels electrons move and the amount of energy they possess