What is the state of matter in which atoms move past each other?
Atoms move past each other in liquids.
Matter tends to exist in the lowest energy state. Atoms and molecules are constantly moving. When they are at a high energy state they are moving past each other and not interacting. This causes the matter to be unstable. When atoms and molecules are moving slowly, they interact more with each other and this makes the matter more stable.
A nonsolid state of matter in which the atoms or molecules are free to move past each other as in a gas or liquid?
Solid, liquid, and gas. The atoms in a solid are packed tightly together with little movement. This is what causes the rigid structure of a solid. Atoms in a liquid are spread further apart than a solid, and will roll around each other causing the fluidity. Atoms in gas are not connected and move freely.