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Atomic, elements and compounds.
All substances are made of Atoms.
Some substances are made up of only one type of atom, we call these Elements.
Most substances we come across aren't pure metal, but have different atoms joined together, we
call these Compounds. Chemical bonds hold the atoms tightly together.…

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To save time form drawing atoms, we write down the number of electrons in each energy level, this
is called the Electronic structure.




You can also look at the periodic table
to know what the how many electrons the outermost layer contains, by looking at an elements
group, the periodic…

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Sometimes atoms react together by transferring electrons to form chemical bonds. This happens
when metal react with non-metal atoms. If the reacting atoms are all non-metals, then the atoms
share electrons to form chemical bonds.
When a metal bonds with a non-metal, the metal atom gives one or more electrons…

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Rotary Lime Kiln
To make lots of calcium oxide this reaction is done in a furnace called a lime kiln.
We fill he kiln with crushed limestone
Heat it strongly using a supply of hot air
Calcium oxide comes out of the bottom of the kiln
Waste gases including the…

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Neutralising acids
Calcium hydroxide is an alkali. It reacts with acids in a neutralisation reaction. The products of the
reaction are a calcium salt and water.
Calcium hydroxide is used by farmers to improve soil that is acidic. Because it is an alkali, it will raise
the pH of acidic…

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Sometimes builders add small stones or crushed rocks, called aggregate, to the mixture of water,
cement and sand. When this sets, it forms a hard, rock-like building material called concrete.
This material is very strong, especially good at resisting forces which tend to squash or crush it. By
pouring the…

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Metal oxide + Carbon Metal + Carbon Dioxide
The metal is also formed, as the element:


We call the removable of oxygen from a compound chemical reduction.
Metals that are more reactive than carbon are not extracted from their ores by reduction. The
process used to extract them is called,…

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It has low density
It is a good conductor of electricity and energy
Its malleable and ductile, which means it can be shaped and drawn into wires easily
Although its reactive it does not corrode easily
This is due to aluminium atoms on its surface react with oxygen in the…

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Then we use the impure copper as the positive electrode in the electrolysis cells to make pure
copper.
Metal ions are always positively charged, therefore in electrolysis they are attracted to the negative
electrode. So metals are always deposited at the negative electrode.
Copper sulfate + iron iron sulfate +…

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We can make copper and aluminium harder by adding other elements. We usually alloy gold with
copper when we use it in jewellery. Pure gold wears away more easily than its alloy with copper. By
varying the proportions of the two metals we also get different shades of `gold' objects.…

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