Lesson: Atoms
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Elements are made up of one type of atom.
Gold nuggets are made up
of gold atoms.
Gold nuggets
A sheet of copper is made up
of copper atoms.
Sheet of copper
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Remember, elements are listed on the
Periodic Table.
If a substance is
listed on the Periodic
Table, it is an element
e.g. copper (Cu) and
gold (Au).
Can you name any other
elements?
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The Periodic Table tells us about the atoms
that make up the elements.
Part of the Periodic Table
2
He
10
Ne
18
Ar
Some nonmetals
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Atoms are
extremely small.
Each full stop in your
textbook contains more
than 1000 million atoms.
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Each atom is made up of smaller
parts called sub-atomic particles.
There are three types of
sub-atomic particle:
Protons
Neutrons
Electrons
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A diagram of an atom
nucleus
electrons
neutrons
The size of the nucleus is
large to make the
diagram easier to draw
and understand. In
reality, the nucleus is
much smaller relative to
the size of the atom.
protons
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A diagram of an atom
nucleus
electrons
neutrons
protons
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The three types of sub-atomic particles are
found in different parts of an atom
Protons are found in the nucleus.
Neutrons are found in the nucleus.
Electrons orbit around the nucleus.
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A diagram of an atom
nucleus
electrons
orbit in
shells
neutrons
in the
nucleus
protons
in the
nucleus
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The three types of sub-atomic particles
have different masses
Protons are 1 amu.
Neutrons are 1 amu.
Electrons are 1/1840 amu.
amu = atomic mass unit
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A diagram of an atom
nucleus
electrons
orbit in
shells
1/1840 amu
neutrons
1 amu
protons
1 amu
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The three types of sub-atomic particles
have different charges.
Protons are positive.
Neutrons are neutral.
Electrons are negative.
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A diagram of an atom
nucleus
electrons
orbit on
shells
negative
neutrons
neutral
protons
positive
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Review Questions
1. Label each part in the diagram.
2. What is the charge
of each particle?
A
D
B
C
protons
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Question to think about!
oxygen
How do atoms fit together?
hydrogen
A water molecule containing two
hydrogen atoms chemically
combined to one oxygen atom.