2. Quantum Numbers
A set of numbers, whose values describe the probable location of an electron around a nucleus

3. Bohr & Hydrogen
Bohr’s model was able to explain hydrogen’s electron distribution
Where light and atoms combine:
Energy Overlap:
Summary of Niels Bohr: Bohr calculated the wavelengths of light that would be emitted by excited Hydrogen atoms. Bohr connected the unseen world (atoms) to the seen (observable, predictable spectral lines).
But his model could not explain atom’s with more than one electron

4. Laws of Physics
In physics, you study “Classical Mechanics”, the study of the motion of macroscopic objects; ie planets around a star, a ball being thrown or a ladder slipping away from a wall etc.

5. Laws of Physics
Where physics and chemistry overlap, is “Quantum Mechanics”; the study of atomic particles. The “classical” rules of motion do not apply because atomic particles behave like waves.

6. Principal Quantum # (n)
Describes an orbital’s size or distance from nucleus
Bohr’s model included this
Energy Level or “shell” of electron
Range:
n = 1 to infinity

7. Secondary Quantum # (l)
The shape of electron orbital
Called “subshells”
Describes motion of electron within a shell
4 domains of motion
s, p, d, f
Range:
from 0 to n-1

9. Magnetic Quantum # (ml)
Each subshell has limited “slots” for electron pairs
The slots are called orbitals
Range:
-l to l

10. Spin Quantum # (ms) Each orbital holds two electrons
Electrons are both negatively charged, but do not repel within an orbital
The have opposite spins to prevent repulsion

11. Summary l l = 0 to n-1 Name Symbol Range Brief Description Principal n
Energy Level (Shell)
Secondary l
l = 0 to n-1
Subshell (s=1, p=2, d=3 & f=4)
Magnetic ml
ml = -l to l
Orbital (orientation in 3D space)
Spin
m s
m s= -½ to +½
Spin (either up or down within same subshell)