1. Bell Work Agenda
Notes: Atomic Spectrum • Have HW out to be
checked
Lewis dot structure • Pick up Bohr Model WS
and complete

2. Atomic Spectrum
January 4, 2013

3. Objectives
1. Explain why scientists know the identity of
the chemical compositions of stars
2. Describe a flame test
3. Describe the Bohr model in terms of
energy

4.  Atoms can absorb and release energy
 When atoms release energy they emit light
 Each atom emits only a certain frequency
of light

5.  When electrons absorb energy they get
excited and jump around
 When jump back to the original position
they release that energy as light

6. Flame Test
Na Li B Cu Ca

7. Quantum hypothesis
 beam of light is both wave and stream of
particles – photons

8. Spectroscope
 White light separates into its color
components by a prism
 Each color corresponds to a different
frequency of electromagnetic radiation

9. Spectroscope
 Observe color components of any light
source

11. Atomic Spectrum
 Light from atoms consist of a number of
individual frequencies rather than a
continuous spectrum
 Pattern of frequencies of a particular
element – atomic spectrum

12.  Atomic spectrum – atoms “finger print”
 Emission – the frequencies the gas emitts
 Absorption – frequencies of all white light
EXCEPT those that are absorbed by the
gas

14. •
 Emission
 Absorption

15.  http://jersey.uoregon.edu/vlab/elements/Elemen

16. Shell model
 A region of space around the atomic
nucleus where electrons may be
 Each shell can hold a limited amount of
electrons

17.  Series of seven shells accounts for the
seven periods
 Number of electrons held in each period is
equal to the shell’s capacity for electrons

19. Valence Electrons
 Electrons in the outermost shell “combining
power”
 Directly exposed to the external
environment
 The first to interact with other atoms