number of e- that can fill first 4 shells
1 | 2 | 1s
2 | 8 | 1s, 3p
3 | 18 | 1s, 3p, 5d
4 | 32 | 1s, 3p, 5d, 7f
orbital definition
a region around the nucleus that can hold two electrons of opposite spin
shapes of s and p orbitals
s = spherical
p = dumbbell
what orbitals make up s, p, d sub shells
s = 1 orbital
p = 3 orbitals
d = 5 orbitals