Answer
b.
Work Step by Step
The first diagram depicts diatomic molecules of two different elements; therefore, the elements are represented by the two differently colored balls. The red balls are grouped in pairs, and the blue balls are grouped in pairs, meaning that the atoms of each element form diatomic molecules. The two elements are in the gaseous state because they are floating freely in the air.
The second diagram shows a compound that is formed between the two elements. Now, instead of two red balls or two blue balls paired together, a red ball is grouped with a blue ball, thus forming a compound of the two elements. The compound is in the solid state because the molecules are stacked together in a rigid configuration and are unable to move.