Sodium is a metal that explodes in water, while chlorine is a poisonous gas. When combined, however, they make edible table salt. Why? Group of answer choices

1) When atoms bond they undergo a chemical change, which changes their physical properties.

2) Two negatives make a positive

3) Salt is actually still poisonous, because of the chlorine in it.

4) The sodium and the chlorine have undergone a physical change, into a solid. The solid part is edible.