The particles of solid are compact to each other, liquid particles are far from each other and gas particles are very far or somehow they're flying that's why gas floats in the atmosphere.
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Solid molecules have tiny spaces between them, and just like in solids, liquid molecules have also spaces but more loose, that only means that there is a force  between these molecules. And in gas , they're loosely packed. They move in random direction. They have large spaces between them because there is no force acting on these molecule.
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