States of Matter

Solid

• Atoms are packed closely together in fixed positions.
• Particles vibrate in place but do not move freely.
• Definite shape and definite volume.
• Lowest particle motion (kinetic energy).

Liquid

• Atoms are close together but not fixed in place.
• Particles slide past one another, allowing flow.
• Definite volume but shape depends on container.
• Intermediate particle motion.

Gas

• Atoms are far apart and move freely.
• Particles spread out to fill the entire container.
• No definite shape or volume.
• Highest particle motion.

Key Concept

The atoms themselves remain the same across all states. What changes is their spacing and movement.

Example: Water (H2O) -> ice, liquid water, steam - same atoms, different arrangements.

Study Tip

Visualize particle diagrams:

• Solid -> tightly packed dots.
• Liquid -> clustered but flowing dots.
• Gas -> widely spaced dots moving randomly.