Which statement correctly compares the motion of atoms in liquid mercury and solid copper? Copper atoms in copper move while staying close together, whereas mercury atoms vibrate around fixed positions. Copper atoms move while staying close together, whereas mercury atoms are independent of one another. Copper atoms vibrate around fixed positions, whereas mercury atoms move around while staying close together.

Explanation:

The solid state of matter is characterized by rigid crystalline structures, in which atoms can vibrate around a fixed position. That is why solids have definite shape and volume, and cannot flow. This is described in the last statement when it states "Copper atoms vibrate around fixed positions"

The liquid state of matter is characterized by the atoms being more separated than in solids. While the atoms in the liquid are not completely free to move, they can slide past the neighboring atoms, which gives them the property to flow. Therefore, the liquids, although they have a defined volume, take the form of the container. This is what the last statement describes as "mercury atoms move while remaining together"