Originally Posted by: meharbrar12

The song is Mercy by Shawn Mendes, the Key is E minor. The chords being used are E minor, G Major, b minor and A Major.[/quote]

Thanks for the info! First, the song is in the key of E minor, meaning any F is an F#. This is like any typical pop song in which the melody will be mostly from notes in the key signature (E minor or relative G major scale). Chord tones will usually be given strong rhythmic placement. Non-chord tones will be used as a way of approaching or connecting the chord tones. But all or most of the notes of the melody will be from the scale. This is a fairly typical way of structuring a melody. Remember that any given chord will have 3 key/scale notes with scale notes between them:

1st chord tone

2nd non-chord tone

3rd chord tone

4th non-chord tone

5th chord tone

So any sequence of notes from the scale could easily have some chord tones combined with some non-chord tones. After all, a melody is a sequence of notes that might have linear scale lines through it. For example: the line E-F#-G-A-B in 1/8th notes would sound fine over an E minor chord. The chord tones would be on stressed downbeats with the non-chord tones as connecting material on the unstressed upbeats. All the notes together form an upward motion. It's only if you land on, stress or stay on a non-chord tone that it might sound unresolved, unsettled or jazzy.

With that in mind let's look at those first 4 bars.

m.1 - E minor chord (i) with melody notes A - B - D. The A is a grace note that leads up to the B (5th of E minor). The D is stressed and is used to create an E minor 7th chord sound. This gives the song a R&B type of sound because of the "jazzy nature" of extended chords. R&B typically draws a little bit from jazz harmony.

m.2 - G major chord (bIII) relative major chord to E minor. The notes B are stressed and they are chord tones. The A is a neighbor tone to the B & only happens for a brief 1/8th note. Later is an F# leading to an E. This results in another extended chord G major7. Nothing unusual, but it does give more R&B flavor. The E is a major 6th, not at all unusual for the style. And the E also kind of serves as foreshadowing of the note that will connect 2 chord tones in the next measure.

m.3 - B minor (v) The D (minor 3rd), F# (5th) & B (1st) are chord tones. The E (4th) serves as a way of connecting the chord tones. Chord tones are on weak beats giving an unsettled sound.

m.4 - A major (IV - a borrowed chord or modulation) - The D (4th) is a grace note that leads to the E (5th) chord tone.

Using so many non-chords in rhythmically stressed ways that connect chord tones gives the melody an unsettled, moody sound. Which is probably intentional because it matches the lyric theme & is typical of an R&B type of love ballad. This approach is used as the lyrics enter as well.

[quote=meharbrar12]I was wondering if someone can give me a explanation just for the first 4 bars of how the non chord tones are being approached and why everything is working together the way it is.

Hopefully my explanation will help!

Keep in mind that while non-chord tones are used and often stressed, they are all simply notes from the key signature being used to connect chord tones.