Order of sublevels?

Question

What is the order of sublevels when dealing with electrons? I know it goes 1s, 2s, 2p, then what?

Answer 1

2p, then 3s, 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f

they do not go in order 3p, 3d etc because 4s needs to be filled before 3d can be, so it comes after 3p, and then 4 p comes after 3d and so fourth.

Answer 2

The order goes:

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 6f, 7d, 7f...

Answer 3

it goes s,p,d,f.
So
1s 2s 2p 3s 3p 3d 4s 4p 4d 4f....