Complete the chart. (remember to enter a "0" if necessary.) atomic number: 10 1s: 2s: 2p: 3s: 3p: 4s: 3d: 4p: 5s:

First, we determine how many electrons can each subshell hold:
s can hold 2 electrons
p can hold 6 electrons
d can hold 10 electrons
f can hold 14 electrons

Second, we start distributing the 10 electrons on the orbitals of subshells based on the arrangement shown in the question :
1s will hold 2 electrons
2s will hold 2 electrons
2p will hold 6 electrons
All other orbitals will will hold zero electrons as the 10 were distributed among the first 2

1s: 2
              2s: 2
              2p: 6 
              3s: 0
              3p: 0
              4s: 0
              3d: 0
              4p: 0
              5s: 0

It's a