C4 - Ocr 21st Century

This power point covers the almost the whole of the specification of C4 Ocr 21st Century.

There are many mind maps on every single topic, I created this just before the exam as a test to see what I know before my exam, but I hope this helps you too :)

Thanks.. :D

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C4 - Revision…read more

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Periodic Table
Rows =
History of Periodic Table...
Column = 1) Johan Dobreiner (German Scientist) ....
Groups - he arranged elements into groups of threes known as triads
- triads had similar properties
- the mean of the atomic mass of the first and last element was equal
to the atomic mass of the middle element
2) John Newlands (English Chemist ) ...
- arranged them in order of the relative atomic mass
- he notices that the first eight elements had similar properties like
an octave
- but this only worked for the first 16th elements
3) Dimitri Mendeleev (Russian Scientist ) ....
- arranged them in order of the relative atomic mass
- he left gaps for missing elements (which have not been discovered
- predicted properties of these missing elements ­ his predictions…read more

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You don't usually Alkali Metal + Water Metal Hydroxide +
Li experiment with Francium Hydrogen
because it is highly reactive
Na and there is only about 30% Lithium + Water Lithium Hydroxide +
( little) amount present Hydrogen
Li + H2O-They
are in group 1
-They react with halogens to
Cs form salt
Fr Alkali Metals Safety precautions ...
As you descend, the -Wear eye protectors
reactivity increases. (goggles)
BUT boiling point
and melting point -Wear chemical resistant
decreases. gloves
-Don't work near water or
-Li ­ gently bubbles in water -Soft and Easy to cut naked flames
-Na ­ Skates and fizzes, produces yellow
flame - Tarnish very quickly as they react with
- K ­ Vigorously bubbles and produces purple oxygen
-Rb ­ Explosive -Low melting / boiling point
-Cs ­ very Explosive ; can break the beaker /
container -Low density
-Highly Reactive…read more

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-They are in group 7
F2 Pale yellow gas -They react with alkali metals to
form salt
Cl2 Pale green gas
-They also take part in displacement
Br2 Brown / Orange Liquid reaction; the more reactive element
displaces the less reactive element
I2 Grey Solid / Purple
Halogens Displacement Reaction...
E.g. Chlorine + Potassium Bromide
Potassium Chloride + Bromine
As you descend, the reactivity
Chlorine displaces Bromine because it is
BUT boiling point and melting
more reactive
point increases.
Safety precautions ...
Practical Importance ... -Wear eye protectors (goggles)
-Chlorine ­ purifies water -Wear chemical resistant gloves
-Bromine ­used in pesticides -Don't work near water or naked flames
-Iodine ­ essential for our diet -When working with Chlorine use a fume cupboard
- starting material for manufacturing as it is toxic
-Usually you don't experiment with fluorine as it is
highly reactive…read more

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Nucleus: Consists of neutrons and
protons. Electrons Protons Neutrons
Protons have positive charge, while
neutrons have no charge. Mass 0 1 1
Nucleus is very heavy and has an
overall positive charge Charge -1 +1 0
Electrons ­ negatively
charged. They orbit the
shells in layers
Atomic Structure
1) Dalton Atom Theory ­ Everything is made of atoms. They cannot be
destroyed or created but instead are conserved during chemical changes
2) Rutherford Experiment- He did an experiment where he had a beam of
alpha particles pointing towards a very thin gold foil and a passage through
the detected foil. Some positively charged alpha particles were deflected and
repelled . This is when the nucleus was introduced to the atomic structure
3) Bohr ­ He improved on Rutherford's model and proposed that the electrons
moved around the nucleus in layers of a shell
4) Chadwick ­ He discovered neutrons; particles with no charges.
The present atomic structure now consists of a nucleus which has protons (positively
charged particles) and neutrons (no charged particles). There are also electrons
which orbit the nucleus in layers of shell.…read more

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For example ...
-Atoms want to lose or gain electrons so they Sodium (metal) and Chlorine (non-metal)...
give or take
-Sodium has one electron in the outer shell, so
-They have a charge (positive / negative) they want to lose it and therefore the ion is Na+
metals have positive charge / non-metals
have negative charge -Chlorine has seven electrons in the outer shell, so
they want to gain one and therefore the ion is Cl-
-They have high melting / boiling points
-Therefore they bond and form the ionic
-They form solid white crystalline compound NaCl
-A giant crystalline structure
-Reaction between non-metals and metals
Ionic Bonding
Mg 2+ and Cl-
A second example ... MgCl
Magnesium (metal) and Chlorine (non-metal)...
-Magnesium has two electron in the outer shell, so
they want to lose two and therefore the ion is Mg
-Chlorine has seven electrons in the outer shell, so
they want to gain one and therefore the ion is Cl-
-However Mg has two electrons to lose, while
Chlorine only needs to gain one. Therefore two
Chlorine ions are needed to make this balance;…read more



It's really useful

? Secret - Team GR

Glad it helped :)


Thank you for creating this resource, it's very helpful :)

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