Question

Which substance has vibrating particles in regular, fixed positions

Answer 1

 most likely Ca(s). calcium ( Ca) is a solid, whose particles are packed closely together

Answer 2

Explanation:

In a solid, molecules are held together by strong intermolecular forces of attraction. As a result, they are unable to move from their initial place but they can vibrate at their mean position.  

Hence, in solid substances the molecules have low kinetic energy and they have fixed positions.

Whereas in liquids, the molecules are held by less strong intermolecular forces of attraction as compared to solids. Due to which they are able to slide past each other. Hence, they have medium kinetic energy.

In gases, the molecules are held by weak Vander waal forces. Hence, they have high kinetic energy due to which they move rapidly from one place to another leading to more number of collisions.  

Hence, gases are able to expand more rapidly as compared to liquids.

Therefore, we can conclude that a solid substance has vibrating particles in regular, fixed positions.