Question

four molecule models are shown.
model 1 model 2 model 3 model 4
which molecule is most likely represented by model 1?

• hydrogen chloride, represented by the chemical formula hcl
• sodium, represented by the chemical symbol na
• oxygen gas, represented by the chemical formula o2
• sand, represented by the chemical formula sio2

Explanation:

Model 1 shows molecules with the same type of atoms (diatomic, as each molecule has two identical atoms). Oxygen gas ($O_2$) is a diatomic molecule with two identical O atoms. Hydrogen chloride (HCl) has two different atoms, sodium (Na) is a monatomic metal (not diatomic molecules), and sand (SiO₂) is a compound with a network structure, not simple diatomic molecules. So oxygen gas matches Model 1's structure.

Answer:

oxygen gas, represented by the chemical formula \( O_2 \)