Answer:
The models highlighted in yellow are the mixtures of two compounds.
Explanation:
Compound is a substance which is formed by chemical reaction of different elements.
Example:
Water = H₂O = Which is made up of hydrogen and oxygen atoms.
Carbon Dioxide = CO₂ = Which is made up of carbon and oxygen atoms
In given models the model highlighted red and on left seems like a single molecule. Hence, it cannot be designated as mixture.
The model highlighted in green at left is the mixture but none of the substance is compound as one is single atom of element while the other is molecule of element.
The model highlighted in red at right is also elemental molecule as it is made up of same element atoms. Therefore, it is neither a mixture nor it contains compound.
The model highlighted in green at right is a mixture of two elements one in atomic and the second in molecular form. Hence, there is no compound present in it.
The models highlighted in yellow are both mixtures of compounds as both contains a pair of compounds made up of different elements.
