States of Matter: Particle Arrangement

Steps:

• Recall that solids have particles in fixed positions, liquids have particles that slide past each other, and gases have particles that move freely.
• Identify the state of each option: A is solid (ice), B is liquid (water), C is gas (air), D is gas (water vapour).
• Match fixed positions to the solid state only.
• Confirm A as the example of a solid.

Why A is correct:

• In solids like ice, particles vibrate in fixed lattice positions, as defined by the solid state of matter.

Why the others are wrong:

• B: Liquid water particles move and flow, not fixed.
• C: Gaseous air particles spread out and collide randomly.
• D: Water vapour particles move freely in the gas phase.

Final answer: A