The order do electron fill orbitals within the 3p sublevel is that they spread out, waiting until each orbital has one electron before doubling up.
Step-by-step explanation
According to hund's rule every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied,and all electrons in singly occupied orbital have the same spin.
when every orbital in a subshell is singly occupied by electrons it is then doubled, and the two electrons in same orbital have opposite spins