New
New
Year 8

Compounds and their formation

I can explain the difference between a compound and an element.

New
New
Year 8

Compounds and their formation

I can explain the difference between a compound and an element.

Lesson details

Key learning points

  1. A compound is made of two or more different elements chemically bonded through a chemical reaction.
  2. A compound may have different properties to each of the elements that it is made from.

Common misconception

Compounds will have the same properties as the elements from which they are made.

Compounds usually have completely different properties from the elements from which they are made.

Keywords

  • Chemical compound - A substance made by a chemical reaction where two or more different elements chemically bond together.

  • Chemical bond - A strong force that holds atoms together in a compound. A chemical bond takes lots of energy to overcome and break.

It is best to use many examples of compounds and the elements from which they are formed. Sodium metal and chlorine gas are both dangerous and toxic to humans, however sodium chloride is added to food making, this a good example to use.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
What does each element on the periodic table represent?
A type of molecule
A compound
Correct answer: A type of atom
A mixture
Q2.
According to Dalton's atomic theory, what is an atom?
A tiny ball that can be split
Correct answer: A ball that cannot be broken up
A type of molecule
A type of compound
Q3.
What is a chemical bond?
A reaction that splits elements
Correct answer: A force that holds atoms together in a substance
A method to separate compounds
The process of melting elements
Q4.
Which of the following are the correct symbols for the elements stated?
Su - sulfur
Correct answer: Na - sodium
f - fluorine
Correct answer: O - oxygen
NI - nickel
Q5.
Which of the following is a pure substance?
Air (includes oxygen, nitrogen, argon, carbon dioxide etc.)
Correct answer: Molecules of water (made of hydrogen and oxygen atoms)
Correct answer: Molecules of oxygen (O₂)
Sea water (salty water)
Correct answer: A sample of one metal (e.g. iron)
Q6.
All matter is made up of...
Correct Answer: atoms

6 Questions

Q1.
What defines a chemical compound?
A single element in its pure form.
Correct answer: Two or more different elements chemically bonded.
A mixture of elements without chemical bonding.
A solid element only.
Q2.
In a chemical reaction, what happens when a chemical bond is formed?
Elements lose their properties.
Correct answer: A new substance is created with different properties.
The elements separate physically.
It creates a mixture.
Q3.
Which of the following words can be used to describe the following substance? Look at the diagram below.
An image in a quiz
Element
Correct answer: Compound
Correct answer: Molecule
Mixture
Q4.
Which of the following is a chemical compound?
O₂ (Oxygen gas)
Correct answer: H₂O (Water)
N₂ (Nitrogen gas)
He (Helium gas)
Q5.
Which statement is true about a chemical compound?
It can be separated back into its elements by physical means.
It has the same properties as its component elements.
Correct answer: It is formed by a chemical reaction.
It consists of only one type of atom.
Q6.
Why do compounds have different properties than the elements they are made from?
The elements forget about their properties.
Correct answer: A compound is a completely different chemical to the elements that made it.
Compounds are always changing their properties
Only metals form compounds.