Chem Class- March 3, 2010

BOHR MODEL
- Atoms are electrically neutral
- Two different models can be used to describe the electron configuartion: Energy Level Model and Bohr Model- Electrons occupy orbitals: 2e in the first orbital, 8e in the second orbital (octet)and 8e in the third orbital (octet)


The video is very detailed. It explains the Bohr Model and it’s origin. So far we’ve only grazed the surface... So it’s fine to just ignore the formulas and specifics. The video does explain the Development of the Bohr Model, how electrons give off energy and briefly explains why Rutherford’s atomic model is defective.



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For the element Argon the Energy level model would look like this:
8e- 3rd level
8e- 2nd level
2e- 1st level

40
18 Ar   <-----the top number is the atomic mass and the bottom number is the atomic number or number of protons)

It's also good to note that the number of electrons is equal to the number of protons in a neutral atom, and the number of neutrons is equal to the atomic mass - the number of protons.

The Bohr model diagram for the element Argon would look like this:

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For the element Chlorine the Energy level model would look like this:

7e- 3rd level
8e- 2nd level
2e- 1st level

35
1 Cl

The Bohr model diagram for the element Chlorine would look like this:

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For the element Fluorine the Energy level model would look like this:

 7e- 2nd level
2e- 1st level

19
9 F


The Bohr model diagram for the element Chlorine would look like this:

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Orbital Shapes

- Atomic orbitals each have a specific name and shape

The atomic orbital on the left is 1s and the atomic orbital on the right is 2s. Notice that 2s is just bigger.

               Notice that the ps have the same shape that they are orientated differently (x is along the x axis, y is along the y-axis and z is along the z axis)
















Hybridized Orbitals
- The first of the Bohr levels is the 1st orbital and it holds 2e

- The second level contains 2s, 2px, 2py, 2pz orbitals. They combine (hybridize) to form one 2sp3 orbital.