Skip to content
MeerkatSkool Afrikaans
Summaries · Grade 7 Natural Sciences › Matter: elements, compounds and mixtures
Free summary · Grade 7 Natural Sciences

Matter: elements, compounds and mixtures

Atoms and molecules, elements, compounds and mixtures, and physical and chemical changes. Read one part at a time and tap “I know this”. Then test yourself in the quiz.

Know it already? Jump straight to the quiz

Your progress0 of 3

Element, compound, mixture

ElementCompoundMixture
WhatOne kind of atomElements chemically joinedSubstances mixed, not bonded
ExampleOxygen (O), carbon (C)Water H₂O, carbon dioxide CO₂Air, salt water
Separate?Cannot be split into simpler substancesOnly by a chemical reactionBy physical methods (filter, evaporate, magnet)

All the known elements are arranged in the Periodic Table.

Tap when you could tell someone without looking.

Particles move

Solidtightly packedLiquidclose, sliding pastGasfar apart
When a solid melts, the particles move faster and slide past each other.

When a gas condenses, the particles slow down and move closer together. A saturated solution cannot dissolve any more solute.

Tap when you could tell someone without looking.

Physical or chemical?

Physical (no new substance)Chemical (new substance)
Paper is tornWood burns
Ice meltsIron rusts
Salt dissolvesA new gas bubbles up
Tap when you could tell someone without looking.

Remember this and test yourself

Remember this: your summary
  • An element is a pure substance of one kind of atom (oxygen); a compound is elements chemically joined (CO₂, H₂O).
  • A mixture is not chemically bonded: air is a mixture; most of the air is nitrogen.
  • The atom is the smallest particle of an element; a molecule is two or more atoms together.
  • Physical change: no new substance (paper torn). Chemical change: new substance (wood burning, rust).
  • In a chemical reaction the mass is always conserved.

Write these points in your book. Read them again the night before the test.

Memory trick

Element = one kind of LEGO brick. Compound = bricks clicked together. Mixture = loose bricks in one box.

Flash cards · Tap to turn over

Important words

First say what the word means, then turn the card over.

Test yourself · Part 2

True or false?

Read the question and the answer. Is the answer right? Tap True or False.

    Now the real quiz!

    The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.

    Take the quiz: Matter: elements, compounds and mixtures
    All Grade 7 Natural Sciences summaries
    For parents
    • Read one part together and ask your child to tell it back in their own words.
    • The ticks (“I know this”) are saved on this device only. We never ask for names or emails.

    Follows CAPS for Grade 7 Natural Sciences. Always check your teacher’s notes and textbook too.

    Free PDF