CHEMICAL
PATTERNS
Module 3
By the end of this lesson I should be
able to……..





Predict the electron arrangement in atoms
using the periodic table.
Appreciate that atoms like to have full orbits
of electrons if they are to be stable.
Understand the link between electron
arrangement and reactivity.
Know which elements are the halogens.
Know the properties of the halogens
Using Power Point

If it is written in white – it should be in
my exercise book!

If it is written in red – it need not be in
my exercise book.
The Atom
The Atom
Arranging electrons
Element
Li
Na
K
Fl
Cl
Br
Ne
Ar
Kr
Atomic
no.
Electron
arrangement
Periodic
table group
Arranging electrons
Element
Atomic
no.
Li
Na
K
Fl
Cl
Br
Ne
Ar
Kr
3
Electron
arrangement
Periodic
table group
Arranging electrons
Element
Li
Na
K
Fl
Cl
Br
Ne
Ar
Kr
Atomic
no.
3
Electron
arrangement
2,1
Periodic
table group
1
Arranging electrons
Element
Li
Na
K
Fl
Cl
Br
Ne
Ar
Kr
Atomic
no.
3
11
Electron
arrangement
2,1
2,8,1
Periodic
table group
1
Arranging electrons
Element
Li
Na
K
Fl
Cl
Br
Ne
Ar
Kr
Atomic
no.
3
11
19
Electron
arrangement
2,1
2,8,1
Periodic
table group
1
Arranging electrons
Element
Li
Na
K
Fl
Cl
Br
Ne
Ar
Kr
Atomic
no.
3
11
19
9
17
35
10
18
Electron
arrangement
2,1
2,8,1
Periodic
table group
1
Groups in the Periodic Table


Elements in the same
group always have the
same number of
electrons in their outer
orbitals.
All members of Group
1, the Alkali Metals,
have 1 electron in their
outer shell.
Groups in the Periodic Table

All members of
Group 2 have 2
electrons in their
outer shell.
 All members of
Group 7, the
halogens, have 7
electrons in their
outer shell.
Groups in the Periodic Table

All members of
Group 8, the Noble
Gases, have 8
electrons in their
outer shell.
Stable (happy) atoms!

Atoms will always try
and get full outer
shells of electrons.
 If the outer shell is
full the atom is
stable!
 Atoms will always try
and react in order to
end up with a full
outer shell!



Group 1 metals will
react in order to lose
their outer electron.
This means they will
have a positive charge
after they have reacted.
Because the lose one
negative charge they
are left positive overall.



Group 7 halogens will
react in order to gain an
extra outer electron.
This means they will
have a negative charge
after they have reacted.
Because the gain one
negative charge they
are left negative overall.
Move into room
143!
Looking at the
HALOGENS!
The Halogens
Element
Symbol
Atomic
no.
Fluorine
Fl
9
State at room
temperature
Boiling
point OC
Fluorine

A very pale yellow
gas
 Incredibly corrosive
– it can not be kept
in a glass jar
because it would rot
the glass.
 These containers of
fluorine are made of
quartz.
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Boiling
point OC
Fluorine
Fl
9
pale yellow - 188
gas
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Fluorine
Fl
9
pale yellow - 188
gas
Chlorine Cl
17
Boiling
point OC
Chlorine

A green gas
 Very poisonous
 Used in the First
World War in the
gas attacks that
blinded and killed
thousands of
soldiers (used by
both the Germans
and the British)
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Fluorine
Fl
9
pale yellow - 188
gas
Green gas - 35
Chlorine Cl
17
Boiling
point OC
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Fluorine
Fl
9
pale yellow - 188
gas
Green gas - 35
Chlorine Cl
17
Bromine Br
35
Boiling
point OC
Bromine

A brown liquid
 Will boil and turn
into a gas with very
little heating.
 Very poisonous –
can dissolve your
lungs.
 Said to be put in the
tea of troops to
supress sexual
desires!
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Boiling
point OC
Fluorine
Fl
9
- 188
59
Chlorine Cl
17
pale yellow
gas
green gas
Bromine Br
35
brown liquid
- 35
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Boiling
point OC
Fluorine
Fl
9
- 188
59
Chlorine Cl
17
pale yellow
gas
green gas
Bromine Br
35
brown liquid
Iodine
53
I
- 35
Iodine

A dark purple solid.
 A strange substance
which turns from a
solid to a gas when
heated – without
first turning into a
liquid.
 Used in antiseptic to
kill bacteria.
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Boiling
point OC
Fluorine
Fl
9
- 188
Chlorine Cl
17
pale yellow
gas
green gas
Bromine Br
35
brown liquid
59
Iodine
53
purple solid
184
I
- 35
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Boiling
point OC
Fluorine
Fl
9
- 188
Chlorine Cl
17
pale yellow
gas
green gas
Bromine Br
35
brown liquid
59
Iodine
I
53
purple solid
184
Astatine
At
- 35
Astatine

A black solid.
 Very dangerous and
usually radioactive.
 There is less than
30g in the entire
Earth at any one
time!
 Has no use what-soever!
The Halogens
Element
Symbol
Atomic
no.
State at room
temperature
Boiling
point OC
Fluorine
Fl
9
- 188
Chlorine Cl
17
pale yellow
gas
green gas
Bromine Br
35
brown liquid
59
Iodine
I
53
purple solid
184
Astatine
At
85
Black solid
337
- 35
(estimated)
The Halogens
Fluorine
 Chlorine
 Bromine
 Iodine

most reactive
least reactive
The Halogens
Fluorine
 Chlorine
 Bromine
 Iodine

most reactive
least reactive
• all have 7 electrons in their outer shell
• all react to pick up an extra electron so that
they have full outer shell and are stable!
200
I
Boiling160
point OC
120
80
Br
40
0
-40
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Cl
-80
-120
-160
-200
Fl
Atomic number
200
I
Boiling160
point OC
120
80
Br
40
0
-40
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Cl
-80
-120
-160
-200
Fl
Atomic number
Graph showing the boiling point of
the halogens
200
I
Boiling160
point OC
120
80
Br
40
0
-40
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Cl
-80
-120
-160
-200
Fl
Atomic number