First of all if you are writing lyrics, you don't have to have a melody, chord chart, lead sheet or anything else to safely copyright your lyrics.
With music, you need to have a full score in most cases.
Here is why:
You can't copyright any note, any chord, any sound (tone) that exists, period.
If you create a new note (not likely) or a new chord (not likely) or a new sound (tone)(possible but for what?
Since record labels and artists are going to change whatever they want on/in your music/lyrics, it's a waste of time to do a full score and upload a CD with the song complete and radio ready.
