Which of these isn't a characteristic of particles of matter?
Particles of matter are always tightly packed.
Matter is anything that has mass, occupies space and can be perceived by our senses. Particles of matter have space between them, always in random motion and attract each other. But particles of matter have varying spaces between them. Particles of matter are tightly packed in solids, less tightly packed in liquids compared to solids and far apart in gases.