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Science Interactive LTD. PO BOX 50764 LONDON NW6 9AT email: [email protected] web: www:science-interactive.co.uk
Unit 1: The Digestive System
Unit 2: The Circulatory SystemUnit 3: Healthy Body and ImmunityUnit 4: The Respiratory SystemUnit 5: Nervous System and the SensesUnit 6: Human HomeostasisUnit 7: Hormones and the Endocrine SystemUnit 8: Drugs and Bad Body Maintenance Unit 9: Photosynthesis in Green PlantsUnit 10: Water Transport in PlantsUnit 11: Flow of Energy and Elements through the EnvironmentUnit 12: Mitosis and MeiosisUnit 13: Inheritance and SelectionUnit 14: Evolution and Human Impact
Unit 15: Genetic EngineeringUnit 16: The Periodic Table and its ElementsUnit 17: The Alkali MetalsUnit 18: Metals and their PropertiesUnit 19: The Transitional Metals
Unit 20: Crude Oil and its ProductsUnit 21: Rock CycleUnit 22: Elements, Molecules and CompoundsUnit 23: Ionic and Covalent CompoundsUnit 24: The Halogens, their Uses and CompoundsUnit 25: The Noble Gases, their Properties and UsesUnit 26: Rates of ReactionUnit 27: Energy
Unit 28: Generating Electricity and its Domestic UseUnit 29: ElectricityUnit 30: Light and the Electromagnetic SpectrumUnit 31: RadioactivityUnit 32: Newton's Forces and the Effects of ForcesUnit 33: Earth and SpaceUnit 34: The Earth and Plate TectonicsUnit 35: The Alkaline Earth MetalsUnit 36: Sound and HearingUnit 37: Natural ForcesUnit 38: Cells, Tissue, Organs and Organs systems
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Science base multimedia CD-ROM for PC is a collection of 38 units or tools totalling over1150PowerPoint slides. Each unit covers a wide range of different delivery and learning styles, offering anexciting way to involve your pupils during lessons or revision sessions. All styles of teaching and
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Unit 25
The Noble Gases, their Properties and Uses
Fluorine Bromine
Iodine
9P+
10N
9E-
Chlorine
17P+
18N
17E-
35P+45N
35E-
53P+74N
53E-
F
Cl
Br
I
9
17
35
53
19
35
80
127
Helium Neon
Krypton
2P+
2N
Argon
18P+
22N
10P+10N
36P+48N
He
Ne
Ar
Kr
2
10
18
36
4
20
40
8436E-
10E-2E-
18E-
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Understand: Keywords:
1. That group VIII elements are called the Noblegases.
2. The physical and chemical properties of group
VIII elements, the Noble gases.3. That they have similar chemical and physicalproperties based on their electronicconfiguration.
4. That because of their full outer shells, theNoble gases do not form compounds with othermetal or non metal elements.
5. Understand that their discovery in theatmosphere was hampered by their stability.
6. Some of the main uses of the Noble gases.
Elements, Noble, Gases, Unreactive,Electrons, Physical, Properties, Inert,Monatomic, Helium, Neon, Argon & Krypton.
Unit 25: The Noble Gases, their Properties and Uses
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Physical properties of the Noble gases one
He2
Helium
He2
He2
Helium
Ne10
Neon
Ne10
Ne10
Neon
Ar18
Argon
Ar18
Argon
Kr36
Krypton
Kr36
Krypton
Group VIII of the periodic table contains a family of very stable non-metals known as the
Noble gases. This group contains h________, neon, argon and krypton. They are all
monatomic colourless gases. All but helium are found in low quantities in our atmosphere.
Helium is found trapped under the bedrock along with deposits of n_________ gas.Helium is so light that the Earths gravity is not strong enough to keep it in our
atmosphere. Eventually we will run out of helium as it escapes the Earths gravitational
pull. Give two uses helium and neon ?
The Noble gases:
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Word bank: helium natural
Position of the Noble gases The Noble gases
Diagram
Notes Found in group VIII of the periodic table,all the Noble gases have eight electrons in
their outermost electron shell. They all
therefore have a full outer shell. This is
what makes them very stable monatomicgases.
The Noble gases have similar chemical and physical
properties because they all have eight electrons in their
outer shell. They are all colourless monatomic gases
which do not form ionic or covalent compounds with
any other elements. They also have extremely lowmelting and boiling points.
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The discovery of the Noble gases
The noble gases were not discovered until about the turn of the last century. Because
the Noble gases are highly un-reactive, they remained hidden in the a____. Helium
was discovered with deposits of natural gas found under the bedrock. In 1892,
scientists discovered that, when all the nitrogen and oxygen from a sample of air wasreacted with hot magnesium, there was around one percent of the gas that would not
react. This small fraction contained n______, argon and krypton.
Discovery of the Noble gases:
100
50
0
Nitrogen Oxygen Noble gases CO2
% composition of noble gases1
0.5
0
Argon Neon Helium Krypton
% composition of noble gases1
0.5
0
Argon Neon Helium Krypton
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Word bank: air neon
Percentage composition of noble gases in air Using helium
Diagram
Notes The Noble gases were not discovered until 1892 due to their
stability. They make up only 1% percent of the atmosphere.
Although they are stable they are still useful.
Hydrogen although having
greater lift has now been
replaced by stable helium.
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Helium and its uses
Helium is the least dense of the Noble gases. A balloon full of helium will have lift in
normal air. Although hydrogen gives more l_____ because it has the lowest density of
any of the elements it is also highly reactive. Helium makes for a safe alternative and
is used in airships and partyballoonsHelium is also used by deep seas divers insteadof nitrogen. It has a low solubility and therefore reduces the risk of divers suffering
the bends. This is when nitrogen in the blood comes out of solution and begins to
bubble in the b_______. This can be fatal. Why is this condition called the bends !
Helium and its uses:
He2
Helium
He2
He2
Helium
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Word bank: lift bubble
Helium Using helium for lift Helium balloons
Diagram
Notes Helium is a low density stable gas that gives
lift to objects like balloons in air. Hydrogen
is better but it is also very unstable and can
react with the oxygen in the atmosphere
forming water. This is an explosive reaction.
Helium is also used for
party balloons. They are
able to rise above the air.
They also (when breathed
in) make you sound like
Mickey Mouse.
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Neon and its uses
Neon is the most widely used Noble gas. Neon is used to make fluorescent light tubes,
which can take on many colours. When you pass a high v_______ current across a
tube full of n______, it glows and gives off light. The tubes can be coloured using
various dyes making them ideal for use in advertising signs around the World. If youtake a trip to Londons Piccadilly Circus, then you will see hundreds of flashing neon
signs all advertising various products and fast food companies. Explain why a neon
light uses less energy than a normal filament bulb ?
Neon and its uses:
Ne10
Neon
Ne10
Ne10
Neon
Neon Neon lights at Piccadilly circus Choose a colour
Diagram
Notes Scientists found out that when you pass a
high voltage current through a tube filled
with neon, it fluoresces. Neon lights are used
in advertising signs. There are also more
energy efficient compared to filament bubs.
By colouring the glass
tube you can colour the
light that is emitted. Neon
lights do not produce any
heat and are therefore
much more efficient.
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Word bank: voltage neon
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Argon and its uses
Argon makes up nearly one percent of the composition of atmospheric air. Argon is
more dense than air, so balloons filled with just argon appear to sink. Argon has two
main uses. Argon is used to replace air or o________ where you need an oxygen free
environment in order to prevent combustion. Filament b______ made from tungstencontain argon to prevent the tungsten from oxidising with oxygen. Argon is also used
during the welding of metals to prevent metals combusting with oxygen. What other
processes require an oxygen free environment ?
Argon and its uses:
Ar18
Argon
Ar18
Argon
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Word bank: oxygen bulbs
Argon Using argon during welding Light bulbs
Diagram
Notes During welding very high temperatures
would cause most metals to begin to react
with oxygen found in air. Argon is flowed
over the weld to prevent the metals reacting.
This techniques is called argonwelding
Light bulbs are filled with
inert argon gas so that the
tungsten filament does not
begin to form tungsten
oxide with oxygen fromthe atmosphere.
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Krypton and its uses
Krypton makes up a very small fraction of the composition of atmospheric air. Like
argon, krypton is more d______ than air. Krypton has one main use. Krypton is used
to produce high energy lasers. These lasers are seen in disco lighting shows. They also
carry sufficient energy to melt metal during their w________. When a high voltagecurrent is applied to the krypton gas, a high energy light is emitted that is used to
produce laser light. Find out from google.co.uk how laser light is produced ?
Krypton and its uses:
Kr36
Krypton
Kr36
Krypton
Krypton Krypton lasers Eye surgery
Diagram
Notes Krypton is used in lasers used for disco
lighting and welding. A high voltage current
is applied to the krypton gas which produces
a high energy beam. This energy is sufficient
to cause melting in metals during welding.
Krypton lasers are use to
remove excess corneal
tissue during laser eye
correction. The cornea is
reshaped to give the
correct focal length.
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Word bank: dense melting
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1: Define the following terms: Elements, Reactivity, Noble Gases, Inert, Ionic and Covalent.
2: Look at the three pictures below. Complete the table.
3: Answer the following using the following table:
a) How much (percent) do the noble gases make up of the atmosphere.
b) This gas was used to give lift to air ships.
c) Argon is used in this device to stop the filament from combusting with oxygen.
d) Whereas, the halogens are diatomic gases, the noble gases are what type of gas.
e) All noble gases are said to be chemically what.
Extension questions and homework
Picture Element Properties and uses
One Krypton
Two Neon
Three Helium
Inert Monatomic One percent Diatomic Reactive
Lift Light bulbs Hydrogen Sign Lasers
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4: Complete the following table.
5: Answer the following questions:
a) What would happen when a light bulb is switched on and it is filled with normal air.
b) Airships are no longer filled with, hydrogen. Helium is now used. Explain why.
c) Explain why there are no known compounds that contain either helium, neon, argon or krypton.
d) Why do helium balloons deflate more quickly than balloons filled with atmospheric air.e) How many electrons do (i) group I alkaline metals have in their outer shell (ii) The group VIII noble gases.
f) Explain why the melting and boiling points of the nobles gases increases as you descent the group.
6: Look at the information in the table opposite:
a) Why were the noble gases discovered very late and why do they
have similar properties.
b) Why is neon used in advertising signs.
c) Why will we eventually rum out of the element helium.
d) Why is argon used to replace air in light bulbs.
e) Give two uses of a krypton laser.
Internet:
Go to google.co.uk and find out the Hindenburgdisaster where hydrogen, not helium was used as a lifting gas for
this airship.
Gas Electrons in outer shell State at room temperature Colour Symbol
Helium 2
Neon Gas
Argon colourless
Krypton Kr
Element When found
Gold < 2000 B.C
Helium 1895
Neon 1898
Oxygen 1774
Phosphorus 1669
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