1. Modern Atomic Theory
Chapter 4 Section 3

2. Modern Atomic Theory
Electrons can be found only in certain energy levels, not between levels
The location of electrons cannot be predicted precisely

3. Electrons Electrons act like waves They are not on one definite path
waves on a vibrating string
They are not on one definite path
Exact location cannot be determined

4. Orbital
A region in an atom where there is high probability of finding electrons.

5. 4 types of orbitals
S, P,D,F

6. Energy Level
Number of orbitals by type
Total Number of orbitals
Total number of Electrons S P D f
X 2 1
1=1 2 3
1+3=4 8 5
1+3+5=9 18 4 7
=16 32

7. Energy Levels Many possible energy levels
The number of energy levels that are filled depends on the number of electrons

8. Valence Electrons Electrons in the outer energy level of an atom
They determine the chemical properties of an atom

9. Electron Transitions
Electrons jump between energy levels when an atom gains or loses energy

10. Photon A unit or quantum of light
Photons of light have different energies
When an electron absorbs a photon it gains energy

11. Atoms absorb or emit light at certain wavelengths
Energy of a photon is related to the wavelength of the light.
Each element emits a different wavelength due to its atomic structure