Answer :
Answer and explanation;
Na - metal
Cl - poisonous gas
NaCl - cyrstaline solid that is edible
An emergent property is a property which a collection or complex system has, but which the individual members do not.
Water emergent properties: cohesion & adhesion, versatile solvent, temperature moderation, freezing.
The properties of a compound can be very different from the properties of the elements that make them, for example, Sodium is an explosive metal, and Chlorine is a toxic gas, however, sodium chloride is a Delicious table salt!