If we were to write a song based on the C scale shown in the image for this section, the first and the last chord of the song would be C in most cases. Another way of saying this is if a song has a root note of C, the song would many times start with a C chord and end with a C chord. The song feels resolved, finished or complete in this way.
If you have some sheet music with chords on it, you would notice that many times the first chord of the song is based on the root note and the last chord of the song is also based on the root note. There are exceptions to this musical rule and we will study those later. If you don’t know what sheet music is, it is a single song published for the general public so that they may learn and enjoy playing a song that they have heard; such as on the radio or in a movie.
So what is a C chord? A chord is a set of notes, usually played with your left hand. As your left hand is playing a chord, your right hand is usually playing the melody. Chords are shown either in the bass clef as notes or they are shown above each measure in the treble clef. In the later case they are sometimes referred to as the guitar chords.
These chords have a ordered pattern we call a progression. This progression is chosen by the composer. And, the progression usually repeats throughout the song. A simple chord progression would be (the following chords):
I-IV-V-I or in the image example above C-F-G-C
Remember, a song usually starts on the root and ends on the root. The chords in between can be many and very different as long as they return to the root. This method of song writing gives the song a feeling of beginning and ending. If I were to write you a song in C and used the 5 chord (in our example G chord) to end the song, you would tell me without really knowing anything about music that the song sounds incomplete. “Why didn’t you finish this song?,” you would ask.