Key Of C Major...
Key of:    C Major
        7 Tones in key:              C,D,E,F,G,A,B        (I, ii, iii, IV, V, vi, vii)
        3 Primary Chords:         C, F, G                     (I, IV, V)
        3 Secondary Chords:     Dm, Em, Am             (ii, iii, vi)
        Dominant 7th chord:      G7                             (V7)
  Danman says..."Check out the chart"...C Major
  Scale Step      Root     3rd    5th   Chord Type
         I         C      E     G   Major
        II        D      F     A   Minor
        III        E      G     B   Minor
        IV        F      A     C   Major
        V        G      B     D   Major
       VI        A      C     E   Minor
       VII       B      D     F   Diminished