1. Chapter 2 Notes: electrons in atoms
The quantized nature of energy transitions is related to the states of electrons in atoms and molecules.
Chapter 12.1

2. Important Terms for this Section
Ionization energy Trends in ionization energy Ionization Energy Ion-i-zation En-er-gy Convergence limit Planck’s constant Scanning tunneling microscope

3. Ionization energy
IE: the amount of energy required to remove 1 mol of e- from the ground state of 1 mol of the gaseous atom.
Once removed, an electron is considered n=∞ level away from nucleus Thus, the transition of n=1 to n=∞ is ionization of the atom

4. Patterns in successive ionization Energies
We can see some evidence of electron configuration in the pattern of successive ionization energies for an atom EX: Aluminum (13)

5. Trends in 1st ionization Energy across periods
Main energy and sub-level energy level trends across the first 3 periods:

6. Trends in 1st ionization Energy across periods
Ionization generally increases across periods
As nuclear charge increases
As e- are removed, there is an increase in electrostatic attraction between protons and electrons remaining
Ionization energy decreases down groups
Farther down group, jumps energy level and farther from nucleus
Less pull on e- from nucleus
There are discontinuities in trend across period which give evidence of sub-levels

7. Planck’s constant and electromagnetic E
c=hf and E=hv so... f=v therefore: E=hv=hf=c h= Planck’s constant h = 6.626x1-0^-34 J⋅s OR 4.135x10^-15 eV⋅s (1st one in the data booklet) Look at page and work through the 2 methods for analyzing graphs to determine frequency and ionization energy