Grade 8 Particles & Matter worksheet
from Gradelings · Name: ______________________
How to explain it
- Particles in solids vibrate in place; in liquids they slide; in gases they move freely.
- Melting, freezing, evaporation and condensation are changes of state. Condensation is gas to liquid.
- Atoms have protons and neutrons (made of quarks) in the nucleus, with electrons around it. An element has one kind of atom.
Example: Water droplets form on a cold glass. Which change of state is this? Water vapour in the air touches the cold glass. Gas becomes liquid. Answer: condensation
Question 1
An atom's centre is called the…
- electron
- nucleus
- shell
- molecule
nucleus
Hint: The nucleus holds protons and neutrons.
Question 2
In which state are the particles packed closely and only vibrate in place?
- liquid
- solid
- gas
- plasma
solid
Hint: In solids, particles are held in fixed positions and vibrate.
Question 3
Physical change or chemical change? Sort each example.
Sort into: 🧊 Physical change · 🔥 Chemical change
- 🧊ice melts
- 🍳an egg cooks
- ♨️water boils into steam
- 🥛a glass is smashed
- 🧂salt dissolves in water
- 🫧baking soda fizzes in vinegar
- 🔩an iron nail rusts
- 🪵a log burns
🧊 Physical change: ice melts, water boils into steam, a glass is smashed, salt dissolves in water · 🔥 Chemical change: an egg cooks, baking soda fizzes in vinegar, an iron nail rusts, a log burns
Hint: In a physical change the substance stays the same (just a different shape or state). In a chemical change a new substance forms.
Question 4
Which particle has a negative charge?
- electron
- nucleus
- neutron
- proton
electron
Hint: Electrons are negative, protons positive and neutrons have no charge.
Question 5
Which of these is a lepton?
- a proton
- a neutron
- an atom
- an electron
an electron
Hint: Electrons are leptons. As far as we know, they are not made of smaller parts.
Question 6
A compound is…
- a gas
- two or more elements chemically joined
- any metal
- a mix of two liquids
two or more elements chemically joined
Hint: Water (H₂O) joins hydrogen and oxygen in a fixed ratio.
Question 7
Which is a physical change?
- Ice melting
- Wood burning
- Iron rusting
- Milk turning sour
Ice melting
Hint: In a physical change, no new substance forms.
Question 8
Why do scientists keep changing their models of the atom?
- New evidence shows something the old model cannot explain.
- Scientists vote on a new model each decade.
- Old models were never tested.
- Atoms change shape every year.
New evidence shows something the old model cannot explain.
Hint: A model is the best explanation we have so far. It is revised when experiments give new evidence.
Question 9
According to the kinetic molecular theory, all matter is made of…
- particles that stop at 0 °C
- solid blocks that never move
- tiny particles that are always moving
- particles that only move in gases
tiny particles that are always moving
Hint: Particles are always in motion. They move faster when the matter is hotter.
Question 10
Which is a sign that a chemical change has happened?
- The substance gets wet
- The substance changes shape
- A gas is produced and a new substance forms
- The substance changes size
A gas is produced and a new substance forms
Hint: Gas bubbles, a colour change, light or heat, and a new substance are clues.
Answer key
- 1. nucleus
- 2. solid
- 3. 🧊 Physical change: ice melts, water boils into steam, a glass is smashed, salt dissolves in water · 🔥 Chemical change: an egg cooks, baking soda fizzes in vinegar, an iron nail rusts, a log burns
- 4. electron
- 5. an electron
- 6. two or more elements chemically joined
- 7. Ice melting
- 8. New evidence shows something the old model cannot explain.
- 9. tiny particles that are always moving
- 10. A gas is produced and a new substance forms
Want more than 10 questions?
In Gradelings the questions change every time and adjust to your child, with hints and kind feedback.