Hey there Michael! Keep in mind that being toward the left of the period table does not make an element a metal. Both chlorine and oxygen are non-metals. That is why, when placed together, they make a covalent bond (formed by two-nonmetals).
Chlorine monoxide refers to ClO while oxygen monochloride refers to OCl. Both are correct, but again it depends on the order of the elements in the compound's formula.
Hope this helps! Let us know if you have any other questions :)