CH07 – Spectral Lines

Class Business

• a word about workload
• what to do when homework takes a long time

Textbook Notes

• goal – record big ideas
• student not expected to understand what is in chapter
• student is expected to know if an idea is present in chapter
• notes are another piece in understanding material
• final thought: if you are 45 minutes into HW and you are not “getting it” or have run out of time, please understand my homework policy, and how I would rather you sleep and come to school refreshed with questions.

Recap

• the picture above is the result of a “continuous” energy spectrum
• continuous vs. quantized world
• can you think of any examples of quantized in your experience?
• it is difficult to process because we have no macro experience of this
• see above: Balmer (1885)

Energy Levels

• electrons can only have certain levels
• when given energy they rise accordingly
• not a stable scenario, with the electron returning to original level
• electrons will seek lowest energy possible
• will “step down”
• every possible combination of returning to lower level is seen
• when returning to lower levels, energy emitted as differences
• the energy emitted is LIGHT
• different energies of light = different colors
• LINES

Examples

• possible transitions with 4 levels
• what are emitted energies?
• what does energy spectrum look like?

Homework

• No HW
• We will use next class to determine spectrum
• please bring a calculator