Question

which best explains the difference between a ball-and-stick model of a chemical compound and a space-filling model?
ball-and-stick models can show compounds in three dimensions, but space-filling models cannot.
space-filing models can show compounds in three dimensions, but ball-and-stick models cannot.
ball-and-stick models show the bonds between atoms, but not the relative sizes of atoms. space-filling models show the relative sizes of atoms, but not the bonds between atoms.
space-filling models show the bonds between atoms, but not the relative sizes of atoms. ball-and-stick models show the relative sizes of atoms, but not the bonds between atoms.

Explanation:

1. Analyze the first two options: Both ball - and - stick and space - filling models are three - dimensional representations of chemical compounds. So the first two options are incorrect as they wrongly state that one of the models cannot show compounds in 3D.
2. Analyze the third option: Ball - and - stick models use sticks to represent the bonds between atoms, and the balls (representing atoms) are usually not to scale in terms of relative atomic sizes. Space - filling models show the atoms as spheres that fill the space between them, so they show the relative sizes of atoms but do not show the bonds (since there are no sticks) between atoms. This option correctly describes the key differences.
3. Analyze the fourth option: This option has the descriptions of the two models reversed. Space - filling models do not show bonds, and ball - and - stick models do show bonds.

Answer:

The option: "Ball - and - stick models show the bonds between atoms, but not the relative sizes of atoms. Space - filling models show the relative sizes of atoms, but not the bonds between atoms."