Question

which of the following is an element?
a. zinc metal (zn)
b. carbon monoxide gas (co)
c. hydrochloric acid (hcl)
d. magnesium chloride salt (mgcl)

Explanation:

An element is a pure substance made of only one type of atom. Zinc (Zn) is an element. Carbon - monoxide (CO) is a compound of carbon and oxygen. Hydrochloric acid (HCl) is a compound of hydrogen and chlorine. Magnesium chloride (MgCl is an incorrect formula, the correct one is MgCl₂) is a compound of magnesium and chlorine.

Answer:

A. zinc metal (Zn)