Half Step Theory ThingsWilliam Wieland
Half Step (a.k.a. semitone or half tone) — the smallest interval (pitch distance) on a piano, e.g. C to D flat (adjacent keys) or E to F
Whole Step (a.k.a. whole tone) — 2 half steps, e.g. C to D
Intervals (measured with half steps)
SCALESWhere are the half steps?
Major 5-finger Pattern:2 2 1 2mifa
Major Scale:2 2 1 2 2 2 1mifatido
 
Minor 5-finger Pattern:2 1 2 2reme
Natural Minor Scale:2 1 2 2 1 2 2reme solle
Harmonic Minor Scale:2 1 2 2 1 3 1reme solletido
Melodic Minor Scale:
Ascending:2 1 2 2 2 2 1remetido
Descending =Natural Minor  
 
Chromatic Scale:1 1 1 ...Everywhere
Whole Tone Scale:2 2 2 ...Nowhere
Octatonic Scale (a.k.a. Diminished Scale):2 1 2 1 ...Every other interval
  or
1 2 1 2 ...
CHORDS
Major Triad:4 3  (Triad Snowpeople)
minor triad:3 4
diminished triad:3 3
Augmented Triad:4 4
 
Dominant Seventh Chord:4 3 3
Major Seventh Chord:4 3 4
minor seventh chord:3 4 3
diminished seventh chord:3 3 3
half-diminished seventh chord:3 3 4