Elements, Compounds and mixtures

1. D O E S I T E V E N M AT T E R ? ?
INTRODUCTION TO
CHEMISTRY

2. ELEMENTS, COMPOUNDS AND
MIXTURES
• An element is a pure substance that cannot be
separated into simpler substances by physical or
chemical means.
• An Element contains only One type of particle. A
substance in which there is only one type of particle is a
pure substance. Elements are made of particles called
atoms.
• So in conclusion, an element is a substance made up of
only ONE type of atom.
• An element has characteristic properties such as
boiling, melting points, hardness, density, shine…etc.
which can be used to identify it.

3. • What if you entered a
supermarket where
all the goods were
placed in no special
order?
Discuss what would
happen.
Is dividing groceries
into sections or
departments useful?
What advantages do
you get from dividing
groceries into
departments?

4. EXAMPLES OF ELEMENTS

5. MORE ELEMENTS

6. HOW CAN ELEMENTS BE ARRANGED
INTO GROUPS??
How would you classify elements?

7. COMPOUND
• A compound is a pure substance composed of two or
more elements that are chemically combined.
Elements combine by reacting with one another.
• A particle of a compound is a called a molecule.
• Molecules of compounds are formed when atoms of two
or more elements bond together.

8. A COMPOUND HAS DIFFERENT PROPERTIES
THAN THE ELEMENTS IT CONTAINS.

9. • A compound can be changed into its elements by
breaking the bonds between the atoms. This is referred
to as a chemical change.
• Heat (thermal energy) or electrical energy can be
used to break down a compound into its elements. This
is called chemical decomposition.
• Example : electrolysis of water
• https://www.youtube.com/watch?v=HQ9Fhd7P_HA
• https://www.youtube.com/watch?v=gZJEDe_HUcw

10. MIXTURE
• A mixture is a combination of two or more substances
that are not chemically combined.
• No Chemical Changes in a Mixture No chemical
changes happen when a mixture is made. So, each
substance has the same chemical makeup it had before
the mixture was formed.
• Mixtures can be separated by physical means.
• Give examples of mixtures you have in your day.
• How can you separate the mixture?

11. CAN YOU USE THE WORDS YOU HAVE
JUST LEARNT TO DESCRIBE A, B AND C?