1. Spectral Series — "Lovely Ballerinas Perform Beautiful Pirouettes"

• Lyman — UV (lowest n_{1}=1, highest energy)
• Balmer — Visible (n_{1}=2; ONLY visible series)
• Paschen — Infrared (n_{1}=3)
• Brackett — Infrared (n_{1}=4)
• Pfund — Far Infrared (n_{1}=5)
• Region shortcut: "UV-V-I-I-I" (one visible, four UV/IR)

2. Quantum Number l Values

• s = 0 (zero lobes extra; sphere)
• p = 1 (1 node plane; dumbbell)
• d = 2 (2 node planes; cloverleaf)
• f = 3 (3 node planes; complex)
• Memory: "SPDFs" — SubParts Describe Fancy shapes

3. Electron Capacity

• s: 2 (2×1)
• p: 6 (2×3)
• d: 10 (2×5)
• f: 14 (2×7)
• Pattern: 2, 6, 10, 14 (increases by 4)

4. Anomalous Configurations

• Cr — "Chromium Craves Chrome" (3$d^{5}$ half, 4$s^{1}$)
• Cu — "Copper Cuts to Complete" (3$d^{10}$ full, 4$s^{1}$)
• Both LOSE one 4s electron to fill/half-fill d

5. Aufbau Diagonal Rule (n+l rule)

• 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p...
• Remember: 4s fills BEFORE 3d; BUT 4s empties BEFORE 3d in cation formation

6. Node Formula — "TRAIN" (Total = n−1, Radial = nAIN)

• Total = n − 1
• Radial = n − l − 1 (= Total − Angular)
• Angular = l
• Image: total nodes = radial + angular
• Note: angular = l always, radial = fill what remains

7. Key Constants to Memorize

• h = $6.626 \times 10^{-34}$ J·s
• c = $3 \times 10^{8}$ m/s
• R_H = $1.097 \times 10^{7}$ $m^{-1}$
• mₑ = $9.1 \times 10^{-31}$ kg
• 1 eV = $1.6 \times 10^{-1}$^{9} J
• hc = 1240 eV·nm (handy shortcut)