In the introductory particle model of the ordinary states of a substance, inter-particle attractions are strongest in _____ and weakest in _____.

Explanation

In the introductory particle model for the ordinary solid, liquid and gaseous states of a substance, attractions are strongest in the solid and weakest in the gas. Solid particles stay close together, while gas particles are widely separated. This is a qualitative comparison of the states, not a universal numerical ranking of unrelated substances.