How are particles represented in the simple particle model of matter?
As small solid spheres.
AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher · 5.2.2.1
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How are particles represented in the simple particle model of matter?
As small solid spheres.
How are particles arranged in a solid?
Close together in a fixed arrangement.
How are particles arranged and able to move in a liquid?
They are close together but can move past one another.
How are particles arranged and able to move in a gas?
They are far apart and move freely.
What happens to particle motion and possible states when energy is transferred into a material?
Particles move more, and the material can change from solid → liquid → gas.
What happens to particle motion and possible states when energy is transferred out of a material?
Particles move less, and the material can change from gas → liquid → solid.
Does a single atom or particle have the bulk properties of the whole material?
No. Bulk properties belong to the whole material, not to an individual atom or particle.
What changes of state occur at a substance’s melting point?
Melting and freezing of the bulk material.
What changes of state occur at a substance’s boiling point?
Boiling and condensing of the bulk material.
For a pure substance, what state is expected below its melting point, between its melting and boiling points, and above its boiling point?
Why does melting or boiling require energy?
Particles attract each other, so energy is needed to separate them enough for the change of state.
What determines the particles in a substance and the strength of attraction between them?
The substance’s bonding and structure.
How does the strength of attraction between particles affect melting and boiling points?
Stronger attractions require more energy to separate the particles, resulting in higher melting and boiling points.
What is the simple particle model useful for understanding?
Basic ideas about states of matter and changes of state.
How does the simple particle model’s depiction of particle shape differ from real particles?
It shows all particles as solid spheres, but real particles are not literally tiny solid balls.
What does the simple particle model leave out between particles?
Forces between particles.
Why are forces between particles important in explaining changes of state?
They help explain why energy is needed for changes of state.
What differences between substances can forces between particles help explain?
Their different melting and boiling points.
Why is a change of state a physical change?
The substance does not become a different substance; only its state changes.
What change of state is melting?
Solid to liquid.
What happens to particles during melting?
They gain energy and move more, so they can no longer stay in a fixed arrangement.
What change of state is freezing?
Liquid to solid.
What happens to particles during freezing?
They lose energy, move less and become held in fixed positions.
What change of state is boiling, and where does it occur in a liquid?
Liquid changes to gas throughout the liquid.
What happens to particles during boiling?
They move fast enough to separate widely and form a gas.
What change of state is evaporation, and where does it occur in a liquid?
Liquid changes to gas at the surface of the liquid.
What change of state is condensation?
Gas to liquid.
What happens to particles during condensation?
They lose energy, slow down and come closer together.