Hi There, 

I have been playing guitar for many years, but I am the typical follow the Chord Fingering on Ultimate Guitar and just work it out from there when playing songs. I am currently on fundemetals 2 and working hard on the theory and currently trying to figure out the fret board a bit more.  

As far as I can undertsand it, when forming a minor chord (Triad). You would play the First note, Flat third and the Fifth. 

Can someone please help me answer the following. Why when we play the E minor chord in the open position we only play the E (I), and the A (V). The flat third would be the G but we dont play that.?

Thanks

TC