# Atomic structure by dffhrtcv3

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```									                  Atomic structure

Mrs Griffiths
Wellington School

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Atomic Structure
The structure of the atom
The Ancient Greeks used to believe that
everything was made up of very small particles. I
did some experiments in 1808 that proved this
and called these particles ATOMS:

Dalton

ELECTRON –
negative, mass
nearly nothing
NEUTRON –                      PROTON –
neutral, same                positive, same
mass as                      mass as
proton (“1”)                 neutron (“1”)
The Atom
Nucleus                Electron

Shell or Orbit
The Atom Hydrogen
Proton                                    Electron

Hydrogen has one proton, one electron and NO neutrons
The Atom Helium

Proton                                          Electron

Neutron

Helium has two electrons, two protons and two neutrons
Mass and atomic number Charge
Particle   Relative Mass Relative
Proton         1                  1
Neutron         1                  0
Electron        0                  -1

MASS NUMBER = number of
protons + number of neutrons

SYMBOL

PROTON NUMBER = number of
protons (obviously)
The Atom Helium

Proton                                          Electron

Neutron

Helium has two electrons, two protons and two neutrons
The Atom Lithium
Protons                      Electrons

Neutrons
The Atom Beryllium
Protons                                        Electrons

Neutrons

Beryllium has four electrons, four protons and five neutrons.
The Atom Boron
Protons                                            Electrons

Neutrons

Boron has five electrons, five protons and six neutrons.
The Atom Carbon
Protons                                           Electrons

Neutrons

Carbon has six electrons, six protons and six neutrons.
The Atom Nitrogen
Protons                                       Electrons

Neutrons

Nitrogen has seven electrons, seven protons and seven neutrons.
The Atom Oxygen
Protons                                        Electrons

Neutrons

Oxygen has eight electrons, eight protons and eight neutrons.
The Atom Fluorine
Protons                                         Electrons

Neutrons

Fluorine has nine electrons, nine protons and ten neutrons.
The Atom Neon
Protons                                         Electrons

Neutrons

Neon has ten electrons, ten protons and ten neutrons.
The Atom Sodium
Protons                                       Electrons

Neutrons

Sodium has eleven electrons, eleven protons and twelve neutrons.
How many protons, neutrons and electrons?
Periodic table
The periodic table arranges all the elements
in groups according to their properties.

Vertical
columns are                                    Mendeleev
called GROUPS

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   Ne
M
Na                                                  Al   Si   P   S   Cl Ar
g
C
K    Ca                      Fe      Ni        Zn                     Br Kr
u
Ag                          I   Xe
A    H
Pt
u    g

E.g. all group 1 metals       These elements have            These elements
have __ electron in           __ electrons in their          have __ electrons
their outer shell             outer shells                   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
in
electronH the                                                 He
configuration 2,1
Li   Be                                           B    C    N   O   F   Ne
M
Na                                                 Al   Si   P   S   Cl Ar
g
Sodium has 11            C
K    Ca        electrons in the Ni
Fe
u
Zn                     Br Kr
configuration 2,8,1
Ag                          I   Xe
A    H
Pt
u    g
Potassium has 19
electrons in the
configuration __,__,__
Fact 3: Most of the elements are metals:
The Periodic Table
These elements
are metals
H                                                He

Li    Be                                      B    C    N   O   F   Ne
M
Na                                            Al   Si   P   S   Cl Ar
g
C
K     Ca                 Fe    Ni        Zn                     Br Kr
u
Ag                          I   Xe
A    H
Pt
u    g
This line divides
These elements are
metals from non-
non-metals
metals
Fact 4: (Most important) All of the elements in
The Periodic Table
the same group have similar PROPERTIES. This
is how I thought of the periodic table in the first
place. This is called PERIODICITY.
H                                                He

Li   Be                                     B    C    N   O   F   Ne
M
Na                                          Al   Si   P   S   Cl Ar
g
C
K    Ca                 Fe    Ni       Zn                     Br Kr
u

E.g. consider the group 1 metals. They all:
Ag                  I            Xe
A   H
1) Are soft       Pt
u   g

2) Can be easily cut with a knife
3) React with water
Group 1 – The alkali metals

Li
Na
K
Rb
Cs
Fr
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          potassium hydroxide + hydrogen
2K(s)   +    2H2O(l)          2KOH(aq)        +       H2(g)

Words – down, one, shell, hydrogen, nucleus
Group 0 – The Noble gases
He
Ne
Ar
Kr
Xe
Rn
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
Group 7 – The halogens

F
Cl
Br
I
At
Group 7 – The Halogens
Some facts…

reactivity
Decreasing
1) Reactivity DECREASES
as you go down the group

(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          Cl      Cl
full outer shell):

3) Because of this fluorine and chlorine are liquid at room
temperature and bromine is a gas
1) Halogen + metal:
The halogens – some reactions
+            -

Na          +      Cl          Na                Cl

Halogen + metal    ionic salt

2) Halogen + non-metal:

H    +        Cl                 Cl       H

Halogen + non-metal      covalent molecule
How shells fill
• The first electron shell can only hold a
maximum of two electrons.
• The second electron shell can hold a
maximum of eight electrons.
• The third electron shell can also hold a
maximum of eight electrons.
• The fourth electron shell can also hold eight
electrons.
Consider an atom of Potassium:
Electron structure

Nucleus
Potassium has 19 electrons.
These are arranged in shells…

The inner shell has __ electrons
The next shell has __ electrons
The next shell has __ electrons                Electron structure
The next shell has the remaining __ electron       = 2,8,8,1
How the shells fill with electrons
Element   Shell 1    Shell 2    Shell 3    Shell 4

Hydrogen 1 electron 0 electron 0 electron 0 electron
H

Helium    2 electron 0 electron 0 electron 0 electron
He
How the shells fill with electrons
Element    Shell 1    Shell 2    Shell 3    Shell 4

Lithium    2 electron 1 electron 0 electron 0 electron
Li

Beryllium 2 electron 2 electron 0 electron 0 electron
Be
How the shells fill with electrons
Element   Shell 1    Shell 2    Shell 3    Shell 4

Boron     2 electron 3 electron 0 electron 0 electron
B

Carbon    2 electron 4 electron 0 electron 0 electron
C
How the shells fill with electrons
Element    Shell 1    Shell 2    Shell 3    Shell 4

Nitrogen   2 electron 5 electron 0 electron 0 electron
N

Oxygen     2 electron 6 electron 0 electron 0 electron
O
How the shells fill with electrons
Element    Shell 1    Shell 2    Shell 3    Shell 4

Fluorine   2 electron 7 electron 0 electron 0 electron
F

Neon       2 electron 8 electron 0 electron 0 electron
Ne
How the shells fill with electrons
Element     Shell 1    Shell 2      Shell 3      Shell 4

Sodium      2 electron 8 electron   1 electron   0 electron
Na

Magnesium 2 electron 8 electron     2 electron   0 electron
Mg
How the shells fill with electrons
Element     Shell 1    Shell 2      Shell 3      Shell 4

Aluminium 2 electron 8 electron     3 electron   0 electron
Al

Silicon     2 electron 8 electron   4 electron   0 electron
Si
How the shells fill with electrons
Element     Shell 1    Shell 2      Shell 3      Shell 4

Phosphorus 2 electron 8 electron    5 electron   0 electron
P

Sulphur     2 electron 8 electron   6 electron   0 electron
S
How the shells fill with electrons
Element    Shell 1    Shell 2      Shell 3      Shell 4

Chlorine   2 electron 8 electron   7 electron   0 electron
Cl

Argon      2 electron 8 electron   8 electron   0 electron
Ar
How the shells fill with electrons
Element     Shell 1    Shell 2      Shell 3      Shell 4

Potassium   2 electron 8 electron   8 electron   1 electron

Calcium     2 electron 8 electron   8 electron   2 electron
Ca
The First Twenty Elements
•   Hydrogen 1,0,0,0
•   Helium    2,0,0,0
•   Lithium   2,1,0,0
•   Beryllium 2,2,0,0
•   Boron     2,3,0,0
•   Carbon    2,4,0,0
•   Nitrogen 2,5,0,0
First 20 Elements continued
•   Oxygen      2,6,0,0
•   Fluorine    2,7,0,0
•   Neon        2,8,0,0
•   Sodium      2,8,1,0
•   Magnesium   2,8,2,0
•   Aluminium    2,8,3,0
•   Silicon     2,8,4,0
First 20 Elements continued
•   Phosphorus   2,8,5,0
•   Sulphur      2,8,6,0
•   Chlorine     2,8,7,0
•   Argon        2,8,8,0
•   Potassium    2,8,8,1
•   Calcium      2,8,8,2
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.
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.
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.
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
Four factors affecting
Reaction Rate

Catalysts       Temperature

Concentration   Surface Area
Catalyst

• A catalyst speeds up or slows
down a reaction but does not get
used up by the reaction.
Temperature

• If we increase the temperature of a
reaction by 100C the rate will
double this means the reaction will
be complete in half the time.
Concentration

• If we increase the concentration of
a reactant the number of particles
increase that in turn increases the
chance of a collision and initiates a
chemical reaction.
Surface area

• The larger the particle size the
smaller the relative area the slower
the reaction.
• The smaller the particle size the
greater the relative surface area and
the faster the reaction.
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 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 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
Halogens
Name     Colour    State    M.P.   B.P.
Fluorine Pale      Gas      -220   -188
Yellow

Chlorine Green     Gas      -101   -34

Bromine Brown      Liquid   -7     59

Iodine   Slate     Solid    114    184
grey
Reactions
•   Sodium and Chlorine react to form 
•   Sodium Chloride.
•   Iron and Chlorine react to form 
•   Iron Chloride.
•   2Na + Cl2  2NaCl.
•   Fe + Cl2  FeCl2.
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.

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