1. Electrons “in Orbit”
Topic 2.1

3. Know the following about the EM spectrum:
The electromagnetic spectrum
Know the following about the EM spectrum:
visible, infrared, and UV regions
describe the variation in:
wavelength
frequency
energy
colors for visible light
Know what is in the red boxes

5. The Electromagnetic Spectrum
High frequency
Short wavelength
High energy
lower frequency
longer wavelength
lower energy

7. Continuous vs. Line Spectrum

8. continuous spectrum produced by light as it passes through a prism
in the case of white light, all colors are seen
there are no levels

9. emission line spectrum
energy is applied to a specific element
this “excites” the element and the light is viewed through a spectroscope
a continuous spectrum is NOT observed, but a series of very bright lines of specific colors with black spaces in-between instead
unique for every element and are used to identify atoms (much like fingerprints are used to identify people)

10. Give off energy when falls back down to normal energy level
More on emission line spectrum
Give off energy when falls back down to normal energy level

11. the process
electrons surround the nucleus in specific orbitals or energy levels
when electrons are excited (heat/electricity) they can move to a higher energy level
when they move back down they emit energy in the form of electromagnetic radiation
because electrons can only exist in certain energy levels, only certain transitions can occur
the color of the light emitted depends on the frequency of the emitted photon

12. this is a repetitive slide- just couldn’t bear to delete it
an electron in the atom gains (absorbs) energy from heating
electron jumps up an energy level.
electron is now unstable (unwelcome) in this level and is “kicked out”
when the electron loses the energy and come back to the original level, light is emitted

13. The Atomic Emission Spectrum of Hydrogen
the emission spectrum of hydrogen is the simplest emission spectrum because there is only one electron
if had more than one electron, they would influence the other’s position
it is not uniform, but concentrated into bright lines, indicating the existence of only certain allowed electron energy levels
Electron “jumping” website
McGraw Hill animation link

15. convergence up here (levels are close together)

16. More about energy levels
energy levels of atoms are NOT evenly spaced like the rungs of a ladder
the higher the energy level, the smaller the difference in energy between successive energy levels becomes
the energy difference between levels becomes less as the level number increases
this means that the lines of a spectrum will converge (get closer together with increasing energy)

18. IB-- this is referred to as convergence of the spectral lines

19. This is referred to as convergence of the spectral lines.