42 can be divided by 2 once. The result, 21, is not divisible by 2.
I think 7x3 is = to 21
There is only one 2s orbital in an atom.
25 of them
310.
2000
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
1
36
26
42