Sophie is right. But there are some general guidelines... GUIDELINES not rules, for the whole 'mood' thing. Do not let them limit you, let them guide you. If you manage to write a tune in with major chords, in major key, that sounds sad it doesn't matter if it goes against the general guidelines i'm about to list.
Major - bright, happy, upbeat
Minor - dark, sad, brooding, angry
If the tonal center is the:
I chord, Ionian, Major as above bright, happy, upbeat
ii chord, Dorian, jazzy
iii chord, Phrygian, spanish flamenco flavor
IV chord, Lydian, majestic, triumphant
V chord, Mixolydian, bluesy
vi chord, Aeolian, Minor as above dark, sad, brooding, angry
viib5, chord, Locrian, dissonant, out, weird, but i've never made this work
Again generalizations, guides, get broken all the time, probably more 'thinky' than creative BUT can help guide you if you are lost and grasping.