Elements and Compounds

Learning Outcomes:

State the names and symbols of the first
twenty elements

Describe what a mixture, molecule and a
compound is

Write word and symbol equations to show
the formation of compounds

Title Atoms, elements and compounds

An element is a substance that is made of only one type of atom.
Elements are the simplest substances in the universe.

Copper is an
element made up
of copper atoms
only.

Carbon is an
element made up
of carbon atoms
only.

Helium is an
element made
up of helium
atoms only.

Elements:

Molecules are made up of two or more atoms. Molecules can be formed
by two atoms of the same element, or by atoms from two or more
different elements.

Oxygen is an element made up
of oxygen atoms only.

How many atoms are there in
one oxygen molecule?

Other elements that form
molecules include hydrogen,
nitrogen, fluorine, iodine,
chlorine and bromine.
These are diatomic elements.

Molecules:

Multiple Choice

Elements are made up of only 1 type of atom

• true

• false

Multiple Choice

TRUE OR FALSE:
Water is a compound.

• True

• False

Write down whether you think each diagram shows an
element or a non-element.

Extension task (ET) Describe the particles in an element
and a non-element.

1

5

4

3

2

Activity 1:

1. Non – element
2.Element
3.Element
4.Non-element
5.Non-element

Stretch: The particles in an element are all the
same (1) but the particles in a non-element are
different(1).

0-2

3-5

6-7

0-1

2-3

4-5

With
stretch

Progress Check:

GREEN PEN

When two or more elements react in a chemical reaction,
the atoms do not just mix together, they become
chemically bonded to one another to make compounds.

Compounds can only be separated into the elements they
were made from using chemical reactions.

hydrogen

oxygen

water
+

+

Compounds:

Multiple Choice

This picture represents which of the following?

• element

• compound

Multiple Choice

This picture represents which of the following?

• element

• compound

Multiple Choice

This picture represents which of the following?

• element

• compound

Multiple Choice

What does the diagram show?

• A mixture of two elements

• A pure compound

• A mixture of two compounds

• A mixture of a compound & element

Multiple Choice

What does the diagram show?

• A mixture of two elements

• A pure compound

• A mixture of two compounds

• A mixture of a compound & element

Multiple Choice

This picture represents which of the following?

• element

• compound

Each element can be represented by a symbol.

For many elements, the symbol is the start of the name, for
example H = hydrogen or Li = lithium. Can you think of any other
symbols like this?

However, some of the symbols are not always as you might expect;
for example, Pb = lead. Can you think of any other elements with
unexpected symbols?

The first letter of an element’s symbol is always a capital letter,
e.g. N (not n) for nitrogen.

If there are two letters in the element’s symbol, the second letter
is always a small letter, e.g. Co (not CO) for cobalt.

Element Symbols:

Multiple Choice

Which is NOT an element?

• Co

• H₂

• S

• NaCl

Multiple Choice

Which is NOT a compound?

• CO₂

• H₂O

• S

• SiO₂

Li2O

CO2
H2O

SO4

Fe2O4

Ba2Cu3O7

H2SO4

Li2HPO4

C6H12O6

We can tell how many elements there are by

counting the number of capital letters. All elements

start with a capital.

Na2PFO3

Li2O = 2

H2O = 2

SO4 = 2

Fe2O4 = 2

MgCl2 = 3

H2SO4 = 3

C6H12O6 = 3

Ba2Cu3O7 = 3

Li2HPO4 = 4

Na2PFO3 = 4

Multiple Choice

Is Iron (Fe) an element or a compound?

• element

• compound

Multiple Choice

Classify Sodium Chloride (NaCl) as an element or compound.

• Element

• Compound

Multiple Choice

Is sugar (C₁₂H₂₂O₁₁) an element or a compound?

• element

• compound

Multiple Choice

How many elements are in C₁₂H₂₂O₁₁

• 3

• 11

• 12

• 22

• 45

Multiple Choice

Is salt (NaCI) a compound or a element

• Element

• Compound

Multiple Choice

Which of the following represents an element?

• H₂O

• H₂

• NaCl

• CaCO₃

Multiple Choice

How many elements are represented in the compound?

Na₂CO₃

• 1

• 2

• 3

• 6

Multiple Choice

What is H₂SO₄

made up of?

• 2 hydrogen, 1 sulfur, 4 oxygen

• 1 hydrogen, 2 sulfur, 4 oxygen

• 2 hydrogen & 4 sodium

• 1 hydrogen & 6 sodium

Multiple Choice

What is H₂SO₄ 
 made up of?

• 2 hydrogen, 1 sulfur, 4 oxygen

• 1 hydrogen, 2 sulfur, 4 oxygen

• 2 hydrogen & 4 sodium

• 1 hydrogen & 6 sodium

Multiple Choice

How many elements are represented in the compound?
Na₂CO₃

• 1

• 2

• 3

• 4