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Chemistry 1
The structure of the atom
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Electrons in
shells
Neutron in
nucleus
Proton in
nucleus
Mass and atomic number
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Particle
Relative Mass
Relative Charge
Proton
1
+1
Neutron
1
0
Electron
Almost 0
-1
MASS NUMBER = number of
protons + number of neutrons
SYMBOL
PROTON (ATOMIC) NUMBER =
number of protons (or electrons)
Symbols
Elements are represented by symbols
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Elements, compounds & mixtures
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Elements – contain
one type of atoms
Mixtures – two or more
elements not chemically joined
Compounds – two or more
elements chemically joined
Periodic table
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Reactive metals
Non-metals
Transition metals
Noble gases
Other metals
Separates metals
and non-metals
H
Li Be
Na Mg
Columns called groups
Mendeleev
He
B C N O F Ne
Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra
Rows called periods
Electron structure
Potassium has 19 electrons.
These electrons occupy specific
energy levels “shells”…
The inner shell has 2 electrons
The next shell has 8 electrons
The next shell has 8 electrons
The next shell has the remaining 1 electron
Electron configuration = 2.8.8.1
Nucleus
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Compounds
Compounds are formed
when two or more
elements are
chemically combined.
Some examples:
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Methane
Sodium
chloride (salt)
Glucose
Covalent bonding
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Atoms sharing electrons is called covalent
BONDING. This bonding occurs between nonmetals atoms.
Each atom make enough covalent bonds to fill it’s
outer shell
Hydrogen has just 1 electron in its outer shell.
A full (inner) shell would have 2 electrons, so two
hydrogen atoms get together and “share ” their
electrons:
Now they both have a full outer shell and are
more stable. The formula for this molecule is
H2.
Ionic bonding
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This is where a metal bonds with a non-metal. Electrons are
transferred between atoms.
Metal atoms lose electrons to form positive ions
Non-metals gain electrons to form negative ions
Na
Sodium in Group 1 has 1 electron on its
outer shell
Cl
Chlorine in Group 7 has 7 electrons in
outer shell.
Sodium transfers 1 electron – so both atoms
have a full outer shell and are stable. Positive
and negative charges attract
+
A positively
charged
sodium ion
Na
Cl
A negatively
charged
chloride ion
Limestone
Limestone is a sedimentary rock made up of mainly
calcium carbonate. It’s cheap and easy to obtain by
quarrying.
Uses
 Building materials
 Making cement. CaCO3 heated with clay
 Making mortar. Cement mixed with sand and water
 Making concrete. Cement mixed with sand and
aggregate
 Neutralising acidic soil & lakes - slaked lime
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Limestone
Positives of quarrying
• Provides jobs
• Provides materials
• Provides neutralisation
products
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Negatives of quarrying
• Destroys habitats
• Produces noise and dust
• Transportations makes
pollution
• Destroys landscape
The “Limestone Cycle”
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Calcium Carbonate (CaCO3)
+
water
Step 1: CaCO3
heated – thermal
decomposition
Step 3: add
carbon
dioxide to
slaked lime
calcium hydroxide
Ca(OH)2 (slaked lime)
Step 2: add
water to
quicklime
calcium oxide + carbon dioxide
CaO (quicklime) +
CO2
Metal extraction
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Metals
 above carbon extracted by electrolysis
 below carbon extracted by reduction
 silver and gold found native
increasing reactivity
Metals can either be found native in the ground (e.g. gold) or
are found as metal ores (e.g. iron = haematite, aluminium =
bauxite)
potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
lead
copper
silver
gold
Reduction
Reduction is the removal of oxygen
The metal ore is reacted with carbon. The
carbon is more reactive so removes the
oxygen from the ore
iron oxide + carbon  carbon dioxide + iron
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carbon
zinc
iron
lead
copper
Electrolysis
Electrolysis is breaking down a substance using
electricity
It needs a liquid to conduct electricity. High
temperatures are needed, which needs a lot of
energy making it expensive
Positive
electrode made
of impure copper
– loses Cu2+ ions
= shrinks
+
+
+
+
Cu2+
Cu2+
-
Solution containing copper ions
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potassium
sodium
calcium
magnesium
aluminium
carbon
Negative
electrode made
of pure copper –
gains Cu2+ ions =
grows
Bioleaching & phytomining
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New mining techniques used to extract copper and decrease
the effects of metal extraction on the environment.
Bioleaching uses bacteria to separate copper from
copper sulphide. The solution produced (leachate)
contains copper which can be filtered.
Phytomining uses plants grown in soil containing
copper, which builds up in leaves. Leaves burnt and
copper in ash can be collected.
Recycling metals
 Fossil fuels running out
 Recycling uses less energy than mining
 Recycling saves money
 Recycling cuts down on landfill sites
 Recycling reduces amount of pollution
Properties of metals
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• Strong
• Can be bent
• Can be hammered
• Good conductors of heat and electricity
Li Be
Na Mg
Al
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra
Copper, Aluminium and Titanium
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Metal
Properties
Uses
Copper
Good electrical
conductor, hard,
strong, can be bent,
doesn’t react with
water
Electrical wires,
plumbing pipes and
tanks
Aluminium
Corrosion
resistant, low
density, forms hard
alloys
Aeroplanes
Titanium
Low density, very
strong, corrosion
resistant
Hip replacements
Alloys
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An “alloy” is a mixture of metals.
Alloys are harder than pure metals
Gold mixed with
copper
Aluminium mixed
with magnesium
and copper
Aluminiun mixed
with chromium
Using Iron
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Iron produced by the blast furnace contains
about 96% iron and 4% impurities. These
impurities make it very brittle and easy to break. Iron is
alloyed to make steel.
Steel with a low
carbon content is
easily shaped
Steel with a high
carbon content is
strong but brittle
Steel with chromium
and nickel is called
stainless steel
Crude oil
Crude oil is a mixture of hydrocarbons
(only contains elements hydrogen and
carbon)
The separate parts – fractions – can be
extracted by fractionating distillation
Crude oil piped in at bottom of
fractionating column, heated, oil
evaporates and
rises. Fractions condense and are
collected
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D
e
c
r
e
a
s
i
n
g
t
e
m
p
e
r
a
t
u
r
e
Alkanes
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Alkanes are saturated hydrocarbons - all of the atoms are
held together by single bonds.
General formula is CnH2n+2 - twice as many hydrogen atoms as
carbon atoms plus an extra two
Methane – CH4
Propane – C3H8
Ethane – C2H6
Butane – C4H10
Patterns
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Increasing length
Longer chains mean…
1. More viscous (gloopy)
2. Less flammable
3. Higher boiling point
Fuels
A fuel is burned to release energy
Coal, oil and gas are fossil fuels.
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Burning Fossil Fuels
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Burning fossil fuels (combustion) releases gases and
particles
Complete combustion (plenty of oxygen) produces carbon
dioxide and water
H
H
C
H
O
O
H
O
C
O
H
O
H
O
O
O
H
H
Carbon dioxide is a “greenhouse gas” – cause global warming
Incomplete combustion (not enough of oxygen) produces
carbon monoxide and carbon
H
H
C
H
H
O
C
O
Carbon monoxide is a poisonous gas
O
Sulphur dioxide
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Burning coal releases sulphur dioxide and nitrogen oxides
Sulphur dioxide and nitrogen oxides cause acid rain and
“global dimming” – sunlight is absorbed by the particles in
the atmosphere.
Acid rain kills trees, causes lakes to become acidic killing
wildlife and damage limestone buildigns and statues
Alternative fuels
Fuel
Pros
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Cons
Ethanol – made
from plant
material
Carbon neutral – CO2 Engines need to be
used for plant to grow. converted. Isn’t
Other waste product is widely available yet.
water
Biodiesel – made
from vegetable
oils
Carbon neutral.
Expensive to make,
Engines don’t need to
would increase food
be converted. Produces prices
less SO2
Hydrogen gas –
made from water
Very clean – no
pollution
Need special,
expensive engines.
Isn’t widely
available. Need to
use energy to make
it.
Cracking
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Useful short chain hydrocarbons can be made from long chain
hydrocarbons by “cracking”:
Gaseous
hydrocarbon
Long chain
hydrocarbon
Heated
catalyst
Liquid
hydrocarbon
Long chain hydrocarbon heated to thermally decompose.
Hydrocarbon vaporises, passes over a catalyst and splits into an
alkane and an alkene
Alkenes
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Alkenes are unsaturated hydrocarbons – there is a double
bond between 2 carbon atoms.
General formula is CnH2n - twice as many hydrogen atoms as
carbon atoms
Ethene – C2H4
Propene – C3H6
Butene – C4H8
Testing for alkenes
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Orange bromine water
Unsaturated alkene
Colourless bromine water
Making ethanol
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1) Ethene reacted with steam in presence of catalyst.
Ethene comes from crude oil – will eventually run out
2) Sugar fermented with yeast. Carbon dioxide also
produced. Sugar grown - renewable
Monomers and Polymers
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Alkenes can be used to make polymers (plastics)
Lots of small alkene molecules – monomers – are joined together
to make very large molecules – polymers
Ethene  poly(ethene)
Propene  poly(propene)
n
C
C
C
C
n
Ethene
Poly(ethene)
Properties & uses of polymers
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•
•
•
•
Light and stretchy – used for plastic bags
Elastic – used to make Lycra
Waterproof – fabric coating
Non-biodegradable – don’t rot
Extracting plant oils
• Extracted from fruits and seeds
• Plant material is crushed, pressed and filtered to
remove impurities
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Emulsions
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Emulsions are a mixture of oil and water. Droplets of one
liquid are suspended in the other liquid.
Emulsions are thicker and have lots of uses – mayonnaise,
ice cream and paint are examples
Emulsifiers stop emulsions from
separating – e.g. egg yolk
Emulsifiers - HT
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Emulsifiers have a
hydrophilic
(likes water,
hates oil) part
emulsifier
water
hydrophobic
(likes oil, hates
water) part.
oil
Saturated and unsaturated oils
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Vegetable oils are unsaturated.
They have a carbon-carbon double bond.
Tested for bromine water
Hydrogenating oil- HT
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Unsaturated vegetable oil can be hardened by reacting
them with hydrogen in the presence of a nickel catalyst
at 60oC.
Hydrogen adds to the carbon-carbon double bond.
Hydrogenated oils have higher melting points = solid at
room temperature. Useful for cakes and pastries
The Structure of the Earth
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Thin crust - 10-100km thick
Mantle – has properties of
a solid but it can also flow
Core – made of molten
nickel and iron. Outer
part is liquid and inner
part is solid
Tectonic plates
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The Earth’s crust is split up into tectonic plates:
These plates are moving apart from each other a few
centimetres every year due to convection currents in the mantle
caused by the radioactive decay of rocks inside the core.
Tectonic theory
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It was once thought that the oceans and the continents
were formed by shrinkage from when the Earth cooled down after
being formed.
Alfred Wegener proposed that there was once a single land mass,
that has changed as tectonic plates moved - TECTONIC THEORY.
The evidence he had was
 the continents look like they “fit” together.
 had similar rock patterns and fossil records.
Tectonic theory
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Wegener couldn't explain how continental drift happened so
nobody believed him
The Answer:
1) Scientists discovered 50 years later that the Earth generates
massive amounts of heat through radioactive decay in the core.
This heat generated convection currents in the mantle causing
the crust to move
2) We also now know that the sea floor is spreading outwards from
plate boundaries
Movement at boundaries
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Movement of plate boundaries can be sudden and disastrous.
Earthquakes and volcanoes happen at the boundaries between
tectonic plates
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Evolution of the Earth’s Atmosphere
Carbon
Methane
Ammonia
dioxide
Phase 1 – volcanoes give out CO2, H2O,
CH4 & NH4. Water vapour and carbon
dioxide condensed to form oceans
4 Billion years
3 Billion years
Oxygen
2 Billion years
Nitrogen
Others
Present day atmosphere =
78% N, 21% O2, 1% noble
gases and about 0.03%
CO2
1 Billion years
Phase 2 – green plants evolved, using
up CO2 and producing O2.
Present day