...Look at the first four bars. What's that F note doing in bar #2? (It is part of a two note slur, if that's the term) Or the F Note in bar three? There's no F note in the G Scale. This could go on.Here's Page Two FYI:
I think what you mean is that there is no F note in a G chord. The song here is in the key of C. I think "they" refer to this as a passing tone, but I am probably wrong about this. There is a F note in the C major scale, however, so it is in the "key" of C.
The same thing happened in the lead-in bar with a D note. Not present in a C chord, but present in a C major scale.
Musical. Pleasing.
(I misspoke in an earlier post and will change it now).