A pure element or a pure compound are homogeneous.
Gold is an element
Aluminium is a chemical element.
Maple syrup is a homogeneous mixture.
Ammonia is a compound, not a gas.
Sugar (sucrose) is a compound not a mixture.
Copper is a chemical compound not a mixture.
Nitrogen is a chemical element not a mixture.
Sodium hydroxide is a chemical compound.
Sugar (sucrose) is a chemical compound not mixture.
Sodium chloride is a chemical compound, not a mixture.
Due to dust particles and dissolved gases in the droplets of rain it is a heterogeneous mixture.
Aluminium is an element, not a mixture.