1. Quantum Mechanics and Configuration
The Bohr Model 2:
Quantum Mechanics and Configuration

2. C12-2-06 ELECTRON CONFIGURATION
OUTCOME QUESTION(S):
C ELECTRON CONFIGURATION
Relate the electron configuration of an element to its valence electron(s) and its position on the Periodic Table.
Include: quantum energy level, shapes, and orbitals.
Write the electron configuration for a variety of atoms and ions using the 3 configuration laws.
Include: shorthand notation and valence configuration
Vocabulary & Concepts 
Principal quantum number (n)

3. de Broglie (1924) – developed an equation that predicts wave qualities for all matter.
If waves of light could contain photon-particles, could matter have wave properties?
Suggests orbits are fixed because electrons (as a wave) could only move as strict
standing wavelength

4. The famous “double-slit” experiment proved the “wave-particle duality” of matter (click the TV link below)

5. Think - trying to catch a frog in the dark with a flashlight…
Problems:
World is 3-dimensional
Bohr’s math failed to explain all spectra
Matter also has wave properties
Heisenberg (1925) - it is impossible to know precisely the velocity and position of a particle at the same time – Heisenberg Uncertainty Principle
Think - trying to catch a frog in the dark with a flashlight…

6. Schrödinger (1926) – developed a wave equation that describes the energies and behaviour of subatomic particles.
Determines the probability of finding an electron in a 3-D volume of space around the nucleus.
At this point, scientists couldn’t really figure matter out experimentally, so they turned to math and computers…

8. Each energy level's boundary is the area of electron location 90% of the time

9. principle quantum number (n)
Bohr’s orbits are now called:
principle quantum number (n)
The (n) number indirectly describes the size and energy requirements of an orbit (electrons have more energy further out)

10. distance from the nucleus 2. Angular momentum (l) shape of orbital
The probable location of every electron is now described by a set of 4 quantum numbers:
This is a lot of detail – focus on the words not the letters (distance, shape, orientation, spin)
QUANTUM NUMBERS
Principal (n)
distance from the nucleus
2. Angular momentum (l)
shape of orbital
3. Magnetic (m)
orientation in 3D space
4. Spin momentum (s)
spin of the election

11. Principal (n) - distance
Number of shapes (l) in each level equals the principal quantum number (n) for that level
NUCLEUS
n = 1 s
n = 2 s p
n = 3 s p d
Like a stadium, the further from the stage (nucleus) the more “sections” of seating for people (electrons)

12. S – sphere P – dumbbell D – clover F - ??
2. Angular momentum (l) - shape
Higher quantum numbers (n) contain many sections of probable electron location – shapes (l)
There are four shapes appearing in this order:
S – sphere P – dumbbell D – clover F - ??
These shapes represent probable locations for finding electrons around the nucleus

13. 3. Magnetic (m) – orientation
Shapes (l) can be made of multiple orbitals (m) that occupy the axes of 3D space (x, y, z)
“s” shape (sphere) – 1 orbital orientations
“p” shape (dumbbell) – 3 orbital orientations
“d” shape (clover) – 5 orbital orientations
“f” shape (indeterminate) – 7 orbital orientations
Think about how many ways each shape can be represented in space – the next picture will help…

14. “s” shape – 1 orbital orientations (just one – in the middle of x, y and z axis)
“p” shape – 3 orbital orientations (along the x, the y or the z axis)
“d” shape – 5 orbital orientations (along x and y, xz, yz…)
“f” shape – 7 orbital orientations (along the …I don’t know what that is)

15. Notice the distance, shape, orientation
OLD way
NEW way
Notice the distance, shape, orientation

16. 4. Spin momentum (s) – spin
Each orbital holds two spinning electrons (s)
Level
Shapes
orbitals
e- capacity 1 s
1 = 1 2
s,p
1+3 = 4 8 3
s,p,d
1+3+5 = 9 18 4
s,p,d,f
= 16 32 n
n types n2
2n2

17. 1s2 2s2 2p6 3s2 3p6 3d10 n = 3 n = 2 n = 1 2e- 8e- 18e- 2e- 8e- 8e-
OLD way
NEW way

18. C12-2-06 ELECTRON CONFIGURATION
CAN YOU / HAVE YOU?
C ELECTRON CONFIGURATION
Relate the electron configuration of an element to its valence electron(s) and its position on the Periodic Table.
Include: quantum energy level, shapes, and orbitals.
Write the electron configuration for a variety of atoms and ions using the 3 configuration laws.
Include: shorthand notation and valence configuration
Vocabulary & Concepts 
Principal quantum number (n)