The Periodic
Table
MENDELEEV
Old image of periodic table
The following slides
show the Structure
of the atom and how
this relates to the
Modern Peiodic
Table
The Atom
Nucleus
Shell or Orbit
Electron
The structure of the atom
ELECTRON
negative, mass
nearly nothing
NEUTRON
neutral, same
mass as
proton (“1”)
PROTON
positive, same
mass as
neutron (“1”)
Mass and atomic number
Particle
Relative Mass
Relative Charge
Proton
Neutron
Electron
1
1
0
1
0
-1
MASS NUMBER = number of
protons + number of neutrons
SYMBOL
PROTON NUMBER = number of
protons (obviously)
How many protons, neutrons and electrons?
Periodic table
The periodic table arranges all the elements
in groups according to their properties.
Vertical
columns are
called GROUPS
Mendeleev
Horizontal rows are called PERIODS
The Periodic Table
Fact 1: Elements in the same group have the
same number of electrons in the outer shell (this
correspond to their group number)
H
He
Li
Be
B
C
N
O
F
Na
M
g
Al
Si
P
S
Cl Ar
K
Ca
Fe
Ni
C
u
Zn
Ag
Pt
E.g. all group 1 metals
have __ electron in
their outer shell
A
u
Ne
Br Kr
I
Xe
H
g
These elements have
__ electrons in their
outer shells
These elements
have __ electrons
in their outer shell
The Periodic Table
Fact 2: As you move down through the periods an
extra electron shell is added:
E.g. Lithium has 3
electronHin the
configuration 2,1
He
Li
Be
B
C
N
O
F
Na
M
g
Al
Si
P
S
Cl Ar
K
Ca
Sodium has 11
electrons inFethe Ni
configuration 2,8,1
Pt
Potassium has 19
electrons in the
configuration __,__,__
C
u
Zn
Ag
A
u
Br Kr
I
H
g
Ne
Xe
Fact 3: Most of the elements are metals:
The Periodic Table
H
These elements
are metals
He
Li
Be
B
C
N
O
F
Na
M
g
Al
Si
P
S
Cl Ar
K
Ca
Fe
Ni
C
u
Zn
Ag
Pt
A
u
This line divides
metals from nonmetals
Ne
Br Kr
I
Xe
H
g
These elements are
non-metals
Fact 4: (Most important) All of the elements in
the same group have similar PROPERTIES. This
is how I thought of the periodic table in the first
place. This is called PERIODICITY.
The Periodic Table
H
He
Li
Be
B
C
N
O
F
Na
M
g
Al
Si
P
S
Cl Ar
K
Ca
Fe
Ni
C
u
Zn
Br Kr
Ag 1 metals. They all:
I
E.g. consider the group
1) Are soft
Pt
A
u
H
g
2) Can be easily cut with a knife
3) React with water
Ne
Xe
Group 0 – The Noble gases
He
Ne
Ar
Kr
Xe
Rn
The Nobel gases
• The Nobel gases have full outer shells and
they are found in group 0 of the periodic
table. Helium, Neon, Argon, Krypton,
Xenon and Radon.
Group 0
•
•
•
•
•
•
•
These are the noble gases.
They have complete electron shells.
The electron shells are full.
They are unreactive.
They are inert.
They do not react.
They include, Helium, Neon, Argon,
Krypton, Xenon and Radon
Group 0 – The Noble gases
Some facts…
1) All of the noble gases have
a full outer shell, so they are
very _____________
2) They all have low melting and boiling points
3) They exist as single atoms rather then diatomic molecules
4) Helium is lighter then air and is used in balloons
and airships (as well as for talking in a silly voice)
5) Argon is used in light bulbs
(because it is so unreactive)
and argon , krypton and neon
are used in fancy lights
The Atom Helium
Proton
Electron
Neutron
Helium has two electrons, two protons and two neutrons
The Atom Neon
Protons
Neutrons
Neon has ten electrons, ten protons and ten neutrons.
Electrons
Group 1 – The alkali metals
Li
Na
K
Rb
Cs
Fr
The Alkali metals
• Lithium, Sodium and Potassium have one
electron in their outer shell and this is why
they are found in group one of the periodic
table.
Group 1
• Lithium, sodium and potassium are all in
group 1.
• They all have one electron in the outer shell.
• They are all metals.
• They react with group 7 to form metal
halides.
Group 1 – The alkali metals
Some facts…
1) These metals all have ___
electron in their outer shell
2) Reactivity increases as you go _______ the group. This is
because the electrons are further away from the _______
every time a _____ is added, so they are given up more easily.
3) They all react with water to form an alkali (hence their
name) and __________, e.g:
Potassium + water
2K(s)
+
2H2O(l)
potassium hydroxide + hydrogen
2KOH(aq)
+
Words – down, one, shell, hydrogen, nucleus
H2(g)
The Atom Lithium
Protons
Neutrons
Electrons
The Atom Sodium
Protons
Electrons
Neutrons
Sodium has eleven electrons, eleven protons and twelve neutrons.
Group 7 – The halogens
F
Cl
Br
I
At
The Halogens
• Fluorine, Chlorine, Bromine and Iodine are
the Halogens and they all have seven
electrons in their outer shell. This is why
they are found in group 7 of the periodic
table.
Group 7
• Fluorine ,Chlorine, Bromine and Iodine.
• They all have 7 electrons in their outer
shell.
• They are all coloured.
• They form metal halides with group 1
metals.
Group 7 – The Halogens
1) Reactivity DECREASES
as you go down the group
Decreasing
reactivity
Some facts…
(This is because the electrons are further away from the
nucleus and so any extra electrons aren’t attracted as much).
2) They exist as
diatomic molecules (so
that they both have a
full outer shell):
Cl
Cl
3) Because of this fluorine and chlorine are liquid at room
temperature and bromine is a gas
Halogens
Name
Colour
Fluorine Pale
Yellow
State
Gas
M.P.
-220
B.P.
-188
Chlorine Green
Gas
-101
-34
Bromine Brown
Liquid
-7
59
Iodine
Solid
114
184
Slate
grey
The Atom Fluorine
Protons
Electrons
Neutrons
Fluorine has nine electrons, nine protons and ten neutrons.
Uses of the Halogens
• Fluorine is put into water supplies to kill
harmful bacteria and to help keep teeth
healthy.
• Chlorine is used in swimming pools to
bacteria in the water.
• Bromine is used in pesticides. Silver
bromide is used in photography.
• Iodine is an antiseptic on cuts and grazes.
The halogens – some reactions
1) Halogen + metal:
+
+
Na
Cl
Halogen + metal
Cl
Na
ionic salt
2) Halogen + non-metal:
H
+
Cl
Halogen + non-metal
Cl
H
covalent molecule
Reactions
•
•
•
•
•
•
Sodium and Chlorine react to form 
Sodium Chloride.
Iron and Chlorine react to form 
Iron Chloride.
2Na + Cl2  2NaCl.
Fe + Cl2  FeCl2.
Displacement
• Fluorine can displace Chlorine, Bromine
and Iodine.
F
Cl
Br
I
Displacement
• Chlorine can displace Bromine and Iodine
but it cannot displace Fluorine
Cl
Br
I
F
Displacement
• Bromine can displace Iodine but it cannot
displace Fluorine or Chlorine
Br
I
F
Cl
Displacement
• Iodine cannot displace Iodine Fluorine,
Chlorine or Bromine
I
F
Cl
Br
Fluorine reacts with sodium
chloride. Which equation is
correctly shows this reaction?
•
•
•
F2 + 2Na  2NaF
F + Na  NaF
2F + 2Na  2NaF
Which will displace?
•
•
•
•
•
•
•
2NaF + Cl2  Yes or No
2NaBr + Cl2  Yes or No
2KI + I2  Yes or No
2LiCl + I2  Yes or No
2NaBr + I2  Yes or No
2NaBr + F2 Yes or No
Cl2 + 2NaBr  Yes or No