There must be many, many chords using the notes in any given scale.
Yes. If we use
C major as the given scale, we could make lots and lots of chords, like :
EFC, etc. Depending on how we run the combinations we could have as many as 210 three-tone chords!
But, many of them will not sound good, like
In major key music the follow lists the basic (prominent) chords:
What's special about such chords that they got such prominence?
Those chords are build of thirds - as apposed to fourths or seconds, etc. Building chords in thirds is call tertian hamony and that is how major key music works. But, that begs the question: why tertian harmony?
The usual answer to that question comes from acoustic science and the overtone series of a vibrating instrument. The essential point is major chords in root position are more acoustically resonant that other chords and supposedly preferred for that reason. The concept is sometimes call the chord of nature.
If you look back to the list of major key triads, you will see that
G are the major chords. Those chords are indeed to prominent chords of the key.
The acoustics of the overtone series do not provide a good explanation for minor chords and other chord types that are very popular. I suppose you can explain those other chords within the context of the acoustical explanation as interesting contrasts to the chord of nature.
Not everyone buys into this acoustic explanation. I'm one of them. To me it works for explaining the stability of the intervals unison, octave, and fifth.
How did one specific chord get to be known as...?
As far as naming is concerned it is based on interval size between various tones of the chords. "Major" and "minor" refer to the third of the chord and how big it is in half steps. A minor third is 3 half steps and a major third is four half steps. In a major chord like
C major (tones
C E G) the
E is the third and it is a major third above the
C. In a minor chord like
D minor (
D F A) the
F is a minor third above the
D. Other interval relationships will be given names like "diminished", "augmented", and so on.
How do certain chords get such prominent names?
To some extent you can take any combination of tones from the major scale and come up with a more or less plausible name. Continuing in
C E G is pretty obvious, it is the tonic chord, the 'home' chord of the key. The tonic chord is definitely a prominent chord.
- we could go to an extreme an use all the tones of the scale, if the tones are ordered the right way we can get a fairly uncommon, but bona fide chord a dominant thirteenth chord
G B D F A C E
- some chords may seem like a jumble of tones, like
C D F but in the right context that could be the supertonic minor seventh chord in third inversion
A B F C also looks like a jumble. We could attempt to name is the leading tone half diminished ninth chord in third inversion... and it would be the first time I have heard of such a chord!
That bullet list should give you an idea of the wide variety of nameable chords. But just because a chord is nameable doesn't mean it is commonly used (prominent) or musically sensible. The prominence of some chords is a combination of tonal centering on stable root position chords, using unstable chord to move to stable chords, and harmonic conventions within various styles.