Key Terms
Upward transition
Photon absorbed
Example
L=1, m_l = +1, 0, -1 theta = arccos(1/sqrt(2)) = 45.0 deg theta = arccos(0) = 90.0 deg theta = arccos(-1/sqrt(2)) = 135.
Definition
De-excitation from a metastable state
State of an electron
Fully specified by (n, l, m_l, m_s)
SPACE QUANTIZATION
L can only point in specific directions — only certain angles with z-axis allowed.
SHELL
All electrons with the same n SUBSHELL: all electrons with the same n and l
NOTATION
Nl (number + letter) — example: 2p = n=2, l=1
Subshell
Maximum electrons = 2(2l + 1)
Shell
Maximum electrons = 2n^2
WHY
For a given l, there are (2l+1) values of m_l; each can have 2 values of m_s → 2(2l+1) electrons per subshell. Summing o
GENERAL RULE
Fill lowest energy first (lowest n, then within n, lowest l)
EXCEPTIONS
Electrons in higher n but lower l subshells can be lower energy because their probability clouds penetrate closer to the
He
1s^2; Ne: ...2p^6; Ar: ...3p^6
TRANSITION ELEMENTS
D subshells filling; complex behavior; crossing of energy levels
LANTHANIDE SERIES
Even more complex; f subshells filling out of simple order