Question

Which of the subshells do not exist due to the constraints upon the azimuthal quantum number?

Answer 1

the azimuthal #, L, is the one associated with the letter in 2s, 2p, 2d...

if L = 0, then you have an "s" orbital
if L = 1, then you have a "p" orbital
if L = 2, then a "d" orbital
etc...

"n" is the principle quantum # and can range from 1 to ∞
"L" can only range from 1 to n-1

so..
if n = 1, L must = 0 and you can only have an "s" oribital.... (first row of the periodic table)
if n = 2, L can be 0 or 1 and you can only have "s" or "p" orbitals.... (2nd row of the periodic table)

for a "d" orbital, L=2 and n must = at least

so 2d doesn't exist