Question

What is difference between 2Cl and Cl2? Which one of these two forms exist in nature? Also give the atomic mass of this element.

Answer 1

Cl2 is a diatomic molecule, whereas 2Cl means 2 units of a negatively charged chlorine anion in a chemical equation. The 2 in front of 2Cl just means that there are 2 single chlorine ions. These ions are NOT bonded to each other. The 2 written in Cl2 means that there are two chlorine atoms covalently bonded to form a chlorine molecule.

P.S.—Technically, in a chemical equation 2Cl should be written as 2Cl^-, because Cl without the superscript “-” implies that there is no charge, where in fact the charge on chlorine should be 1-