what kind of change occurs when sodium and chlorine combine? Describe the matter before and after the change

Sodium is a silver-colored metal which is soft enough to cut with a knife. It is an extremely reactive metal, and is always found naturally in ionic compounds, not in its pure metallic form. Pure sodium metal reacts violently (and sometimes explosively) with water, producing sodium hydroxide, hydrogen gas, and heat:

Chlorine is a poisonous, yellow-green gas, with a very sharp odor, a

Chemical change happen cuz these 2 elements will combine to form a new compound which's NaCl (table salt)