The state of matter with molecules in very loosely packed arrangement is gas.

Here's why:

* Gases have the most freedom of movement. The molecules are far apart and move randomly in all directions. This loose packing is what gives gases their ability to expand to fill any container.

* Liquids have molecules closer together than gases, but they can still move around and slide past each other.

* Solids have the most tightly packed molecules. They are held in fixed positions, giving solids their rigid structure.