1. Electrons in Atoms 13.3 Physics and the Quantum Mechanical Model
13.1 Models of the Atom
Atomic orbitals
13.2 Electron Arrangement in Atoms

2. Physics in Chemistry Speed of light, c = 3 x 108 m/s c =  c = 
 = wavelength (m)
 = frequency (Hz) (Hertz = s-1)
Also  = frequency
Electromagnetic spectrum p. 373

4. Atomic emission spectra =
Group of wavelengths of energy emitted by electrons falling down to lower energy levels after being excited
Unique for each element
Ground state vs. Excited state
E = h
E = energy (J) (Joule)
Planck’s constant, h = x Js
Photoelectric effect =
Metals eject electrons when light shines on them
Proves the particle concept of the dual
wave-particle behavior of light

5. Example: A popular radio station broadcasts with a frequency of 94
Example: A popular radio station broadcasts with a frequency of 94.7 MHz. What is the wavelength of the broadcast?

6. deBroglie’s equation =
Calculate the wavelength of a moving particle, like an electron
 = h / mv
 = wavelength (m)
h = Planck’s constant (Js)
m = mass (g)
v = velocity (m/s)
Heisenberg Uncertainty Principle =
You cannot know both the velocity (speed) and position (location) of a particle at the same time

7. Atomic Orbitals Describe the location of electrons
Orbital = region of space
Principle quantum # (n) = energy level
n = 1, 2, 3, 4, 5 …
with increasing distance from the nucleus
Energy Sublevels = s, p, d, f (see p )
s sphere 1 orbital max 2 electrons
p dumbbell 3 (x, y, z) 6
d clover leaf f
Max 2 electrons in each orbital

9. Order of filling orbitals (p.135)

10. Pauli Exclusion Principle: Hund’s Rule:
Aufbau Principle:
Electrons enter orbitals of lowest energy first
Pauli Exclusion Principle:
Atomic orbital can have at most 2 electrons
Hund’s Rule:
For orbitals of equal energy, 1 electron enters each orbital until all orbitals have 1 electron with parallel spins

11. Electron Configuration and Orbital NotationSi Ni Ar B
Cr and Cu
Al, Ge, Sb, Po

12. Noble gas shorthand notation
Valence electrons and electron dot structure
Link s, p, d, f blocks to periodic table