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Structures and Bonding

The Atomic Structure

Contains the same amount of protons and electrons, making the charge 0.

Protons +1

Neutrons 0

Electrons 1

The Arrangement of electrons in atoms

Each shell represents a different energy level. Lowest energy level is shown by
the shell which is nearest to the…

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By gaining electrons the element turns negative. By releasing electrons the
element turns positive.

Ionic Bonding

Strong forces of attraction between oppositely charged ions electrostatic
force acts in all directions ionic bond

The ionic bonds can result in the particles arranging in a giant structure

The force exerted by an…

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Higher ­ Metals are another example of giant structures. Metal = lattice of
metal ions (positively charged ions)

The electrons in the outer shell can easily move from one atom to the
next. The electrons which have the highest energy levels form a sea
of free electrons surrounding the positively…

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ions. Ions free to move ­
will conduct electricity
Simple Molecules
Covalent Bonds ­ when atoms of nonmetal elements react to form
compounds ­ share electrons in outer shells ­ each atoms gets a
full outer shell.
Substances with this kind of bond tend to have low boiling and melting…

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others and one spare outer electron on each atom. This spare electron
becomes delocalised among the layers of the carbon atoms.
Fullerenes ­ there are other different molecules that carbon can produce. In
these structures carbon atoms join together to make large cages
which can have all sorts of weird…

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either lose or gain electrons. For practical purposes the masses of the
electrons isn't worth bothering about.
Relative Formula Mass ( Mr ) ­ The relative atomic mass is used the work
out the relative formula mass. E.g. Sodium Chloride
(Ar) Na + (Ar) Cl = (Mr) NaCl

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(12x21) + (1x22) + (14x2) + (16x2) = 252 + 22 + 28 + 32 = 334
252 The percentage mass of carbon in the
strychnine. Not the same ­ not strychnine
Higher Working out the formula of a compound from it percentage
Empirical Formula ­ Tells us…

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1 mole of oxygen = 1x32g = 32g
2 moles of water = 2x18g = 36g
The following formula can be used to find out how much of two
chemicals are used to react together. Sodium hydroxide reacts with
chlorine gas to make bleach.
2NaOH + Cl2 NaOCl + NaCl…

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= 60% = Percentage yield
Very few chemicals have a yield of 100% because:
The reaction could be reversible
Some reactants may react to give an unexpected product
Some of the reactants could be left behind on the apparatus
The reactants may not be completely pure
Some chemical reactions produce…

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4) A+B (Eventually the rates of forward and reverse
reactions are the same
In a system that is closed, no reactants or products can get in or out. In a
closed system, as more and more products are made in a reversible reaction
the rate at which these get converted…


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