I was thinking Emadd10 ... is this right? Wasn't sure since the third/tenth is minor in the Em chord. This would be implied since I have already specified we are talking about Em, right?
The name of the chord wouldn't change. It still would be called Em. On instruments like the guitar and the piano, where you have the option to play multiple notes of a chord, it is really common to play twice (or even trice) some notes. So, if you played the notes
E,G,B,G, the chord wouldn't change; no need to add the
add10 to the chord's name.
Shev is right the name would not change, but it would be a different voicing of the chord. There are many, many, different voicing for any chords. A chord is a set of notes so as long as you have the notes E, G, and B in any order or amount of each over 1 is considered an Em chord.
So the following chords are all E minor:
E - G - B E - B - G - E E - E - G - B E - G - E - B - B
The only exception is if the bass note is not the root of the chord then you would specifiy the note in the bass with a slash. For example if G was the bass note in this case the chord's name would change only slightly to Em/G. It's still an E minor chord, but we are specifying what note we want in the bass.
- The chord Em consists of notes E-G-B. As G is already a chord tone, the chord symbol is just Em, even if the voicing contains several notes G.
- If you want to suggest playing G as the lowest note of the chord, the notation would be Em/G. This is called inversion of a chord. However, the chord symbols don't indicate what the top note is supposed to be.
- The term position can be used to indicate the top note, e.g., the Em chord with G in the top voice would be in third position, as the interval between E and G is a minor third. Unfortunately, I find the word position conflated with inversion more often than not, at least in the materials available on the internet, so the term might not be clear for many readers. To make things worse, on guitar (and other string instruments) position indicates the location of the index finger along the neck, adding extra ambiguity.
In E minor, the third is raised by an octave and it is not conventionally written, because the chord already implies it. However, in order to know that the octave of the minor third is stressed, it can exceptionally be written as guitar Em10 (the so-called J.Hendrix Em7/10 "Purple Haze").