Question

alexandra and maddy made an atomic model of a substance as shown. alexandra thinks its an element, but maddy thinks its a compound. which statement explains why either alexandra or maddy is correct?
alexandra is correct because there are two atoms in each molecule, making it a compound.
alexandra is correct because there is only one type of atom in each molecule.
maddy is correct because there are two atoms in each molecule.
maddy is correct because all molecules are compounds.

Explanation:

• An element is a pure substance made of only one type of atom. A compound is made of two or more different types of atoms chemically bonded.
• In the model, each molecule has only one type of atom (both atoms in a molecule are the same). So Alexandra is correct because elements can exist as diatomic molecules (like O₂) with one type of atom.
• The first option is wrong because two atoms of the same type make an element, not a compound. The third is wrong as two atoms of the same type don't make a compound. The fourth is wrong because molecules of elements (like O₂) aren't compounds.

Answer:

Alexandra is correct because there is only one type of atom in each molecule.