18 of them
36
Exactly 18 of them
Exactly 18 of them do, with nothing hanging out and no room to spare.
There is only one 2s orbital in an atom.
2000
310.
25 of them
100 2s for the hundreds digit of 200-30010 2s for the tens digit of 220-23010 2s for the ones digit of 200-300________________________________120 '2s'
unknown
39
1
20 of them.