The atom
Atoms
• Atoms are the thought of as the smallest
part of an element
• They are formed from three different subatomic particles
• These are call protons, neutrons and
electrons
The sub-atomic particles
Particle
Charge
Mass
Proton
+1
1
Electron
-1
1/
1850
Neutron
0
1
Complete the
following table
The Atom
It contains all
This
is
the
the protons
and nucleus
neutrons
This is one
electron
Electrons are
always present
in shells
Atomic Number
This is carbon
12
6
All elements on
the periodic table
are shown like this
C
This is the
elements
symbol
This is the
elements
atomic
number
What does the atomic number tell
us?
• The atomic number tells us how many protons
an element’s atom has. This is the same as the
number of electrons
• So carbon has 6 electrons
• Sodium’s atomic number is 11. So it has 11
electrons
• Oxygen has an atomic number of 8. how many
electrons does it have?
• How many electrons does chlorine have
• Which has more electrons bromine or calcium?
Electron Shells
The first
The second
electron
shell
The third
electron
can have shell
up to
electron
shell
can
have
up
to
two electrons
can have
up to
eight
electrons
eight electrons
Carbon’s Electron Shells
Carbon has 6
electrons
The electron
configuration is
written as 2. 4
There
Two
These
electrons
are
canfour
go
nd
electrons
can
intogo
thein2left
the
first
shell
shell
The outer shell
• The number of electrons in the outer shell
of an atom is the same as the group of the
atom
• For example, carbon has four electrons in
its outer shell and it is in group four
Question Time
How many protons do the
following elements contain?
23
56
119
19
27
Na
Fe
Sn
F
Al
11
26
50
9
13
11
26
50
9
13
Question Time
Question Time
Make your own atom