Naming Triads: The position that a chord is in does make a difference in how it sounds, but it is a fairly small difference. Listen to a G major chord in different positions.

g major chord

A much bigger difference in the chords sound comes from the intervals between the root position notes of the chord.  For example if the b in one of the above chords were changed to a B flat, you would still have a G triad but the sound would be much different.  So chords are named according to the intervals between the notes when the chord is in root position.

g chords

The chords above are all G chords but they are four different G chords.  The intervals between the notes are different so the chords sound different.

Major and Minor Chords: The most commonly used triads form major and minor chords.  All major and minor chords have an interval of a perfect fifth.  A perfect fifth is 7 half steps from the root.  A perfect fifth contains a major third and a minor third.  If the interval between the root and the third is minor, than the chord is a minor chord.  If the interval between the root and the third is major, (with a minor third between the third and the fifth) than the chord is a major chord.