Why does argon exist in nature as individual argon atoms and chlorine exist in nature as 2 chlorine atoms covalently bonded together ?

Argon has 8 valence electrons and no extras, it does not require a bond in order to fill its shells, its satisfied by itself.

Chlorine is missing 1 Electron, if it connects with another Chlorine it will be satisfying both of their needs with a Covalent bond.

Explanation:

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.