Question

Why do some elements exists as molecules and some as atoms ?Give reasons?

Answer 1

Answer:

An element like helium, neon, argon etc. already have this octet of electrons, so they are stable as they are. So, they don't combine with other atoms; so these elements (inert gases) exist as atoms. ... These diatomic molecules have the octet structure and are stable.

Answer 2

atoms with less than 8 electrons in outermost orbital can react with the other atoms and forms molecules .atoms with the 8 electrons in the outermost orbital can exist as atom