Which of these chemical formulas—kcl, xe, co2, or h2—represents both an element and a molecule?

Among the four choices of chemical formula listed above, we are tasked to find that represents both a molecule and the elements. Using elimination method, KCl and CO2 is not anymore part of the choices since it is a compound leaving Xe and H2. H2 is a hydrogen gas and a compound. Therefore the correct answer to the problem above is Xe. Xe can be access in the modern periodic table, thus, it is an element.

Nonmetals usually react by gaining electrons