How many electron levels exist?
1 Answer
As many as the atom needs.
In reality, electron energy levels are "accessed" as soon as the electron "occupies" an orbital in a new energy level. Energy levels of empty orbitals don't really exist. We just like to say they do for simplicity, and draw, e.g.
ul(uarr darr)
for a
The usual orbitals atoms have often used (grouped by angular momenta) are:
1s, 2s, 3s, 4s, 5s, 6s, 7s
2p, 3p, 4p, 5p, 6p, 7p
3d, 4d, 5d, 6d
4f, 5f
No atom has so far used a