Particles in a solid move farther apart on heating - A metal rod expands on heating, when we increase the temperature. The kinetic energy of the particles increases. As a result, the particles leave their fixed positions and start moving freely.

Different particles of different elements have different masses. A gold bracelet (has large mass and density) is much heavier than an identical silver bracelet (has lower density and mass).

Gas particles always spread out to fill the space available to them. For example: It is easier to squash a balloon filled with air than a balloon filled with water.

Gas particles are father apart than liquid particles. For example: You can smell dinner cooking in the kitchen when you are in your bedroom.