​Atoms are made of protons, neutrons and electrons.

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• Protons and neutrons are found in the nucleus, in the middle of the atom.

• Electrons are found around the outside of the nucleus. ​

​Do you remember this diagram from your Science Book?

Mixtures are not pure because there is more than one substance . Mixtures are not chemically bonded together.

Elements and compounds are pure substances.​

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Pure Substances​

Classifying Matter

Some text here about the topic of discussion

Matter can be classified as either PURE SUBSTANCES or MIXTURES

Mixtures​

An element is a pure substance made up of only one type of atom.

​​ELEMENTS​

​EVERY element is listed on the Periodic Table of Elements

A compound is a pure substance made up of two or more DIFFERENT elements chemically bonded together ​

COMPOUNDS​

For example: Water, H₂O, is a compound made up of 2 hydrogen atoms and 1 oxygen atom.

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The two different types of atoms are all bonded together.

• All compounds have a chemical formula which shows us what they are made of.

• Some compounds also have a more common name that we know them by​.

Physical Change

• During a physical change, no new substance is formed.  

• Signs of a physical change include:

  • A change of shape or size

  • A change of state (solid to liquid to gas, or vice versa)

  • An expected colour change (e.g. when you dissolve raro powder in water)

  Physical changes are normally easy to reverse. 

  (unless you have changed the shape/size of something by breaking it)

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Chemical Change

During a chemical reaction, new substances are formed. Chemical bonds are broken and/or formed.

• ​Signs of a chemical change include:

  • An unexpected colour change

  • Bright light is seen

  • Heat being released (feels hot) or absorbed (feels cold), without actively heating or cooling the substance

  • Fizzing /Bubbles being formed (without heating the substance)

  • A new odour

• Chemical changes are very difficult to reverse. i.e. you can't change it back