Question

which elements have molecules as their basic units? check all that apply. iron oxygen bromine helium

Explanation:

To determine which elements have molecules as their basic units, we analyze the type of elemental structure:

• Iron (Fe): It is a metal and exists as individual atoms (or metallic lattice), not molecules.
• Oxygen (O₂): Diatomic molecule (two oxygen atoms bonded), so its basic unit is a molecule.
• Bromine (Br₂): Diatomic molecule (two bromine atoms bonded), so its basic unit is a molecule.
• Helium (He): Noble gas, exists as individual atoms (monatomic), not molecules.

Answer:

B. oxygen, C. bromine