Question

can any 2 atoms pair up to make a new bond?

Answer 1

yes but some atoms make a weaker bond then others

Answer 2

Sure, for example: \[O_{2}\] :-)

Answer 3

Not always. If you have an atom with a complete octet - 8 electrons in its outermost shell, then these atoms are typically inert. So Neon, Argon etc do not bond easily with another atom. Also metal atoms are typically represented as individual atoms.

Answer 4

Right. I missed the "any" part of the question, sorry.