Provides an overview of the points made on the specification for the AQA Chemistry exam board. Includes all topics (note that chromatography, catalysis, NMR and Period 3 is excluded) with the corresponding detailed notes alongside each point.
ATOMIC STRUCTURE
Evolution of Experimental evidence improves our
atomic understanding of the atom
structure Appreciate the knowledge and understanding of
the following:
1803: John Dalton (Billiard Ball Model)
Matter is made of tiny atoms which cannot be
created, divided or destroyed
Atoms of the same element are identical and
atoms of different elements are different
Different atoms can combine to form new
substances
1897: J.J Thompson(Plum Pudding Model)
Discovery of the electron by the cathode-ray tube
experiment
Beam of electron in the tube deflect towards the
positive plate showing the existence of divisible
negatively charged sub atomic particles.
Proposed a model where electrons were
suspended in positive matter
1909: Rutherford’s Scattering (Nuclear
model):
Rutherford shot a beam of positively charged
particles at a thin sheet of gold foil
A few particles were reflected directly back
(therefore positive centre must be small)
Most particles travelled through (most of atom is
therefore empty space)
, Some particles refracted (positive centre is
dense)
This led the idea that the nucleus- small dense
positively charged area is present in atoms.
1913: Nicholas Bohr (Bohr’s model)
Discovering of shells:
Electrons orbit the nucleas on shells at fixed
distance from the nucleus
Each orbital has a different energy associated
with it. Further away orbitals have a higher
energy.
This explains why the atom does not collapse
onto itself due to the like charges.
Further investigations led to the discovery that
the nucleus could be divided into a particle with a
positive charge and mass (proton)
1932: Chadwick’s discovery of neutrons by
investigations that led to discovery of a neutral
particle in nucleus by Frédéric and Irène Joliot-
Curie
Sub atomic Atoms contains positive nucleus (with neutrons
particles and positively charged protons both have mass of
1) and surrounded by orbiting electrons (mass
1/1850)
Isotopes are atoms with a different mass as they
have the same number of protons but a different
number of neutrons.
Mass spec Vaporisation: vaporised as enters the mass
spectrometer
Ionisation: Electro spray ionisation (turned into
gas and passed through needle so solvent
droplets give H+ connected to DC power supply)
or electron bombardment, hit with gun and
electron knocked out.
Acceleration: At chamber, given the same kinetic
energy by electromagnetic
Drift: heavier atoms travel at a faster rate
through the chamber
Detection: gain electron as the particle hits the
detection plate which send an electrical current
Data analysis: looks at time of flight to determine
the existence of isotopes and their relative
abundance.
, Time of Flight in chamber used to determine
the mass of the atoms (requires the time,
distance, kinetic energy of particles)
Electronic Electrons located in orbitals (s,p,d,f) and two Period 3 trends
configuration occupy 1 sub-orbital Group 2 trends of first and
First ionisation energy: energy required to remove ionisation energies
one mole of electron from an atom in its gaseous
state
X(g) --> X+(g) + e-
Across a period, ionisation energies can vary:
Less energy required to remove an electron that
occupies a sub-shell with an electron already in it
due to mutual repulsion
Less energy required to remove an electron from
a d,f,p orbital as it is higher energy and further
away.
AMOUNTS OF A SUBSTANCE
Relative Mass of one atom relative to 1/12 of mass of a
atomic/molec baron-12 atom
ular mass
Avogadro + Avogadro constant is the number of particles in a
mole mole
Concentration of a substance measured in
mole/dm^3
Ideal Gas pV=nRT
Equation R is the gas constant
N is number of moles
T is temperature measured in K (298K standard)
V volume measured in m^3
P measured in Pa (100Kpa standard)
Empirical Simplest whole number ratio of atoms in a
formula molecule
Molecular is actual number of atoms in a
molecule/compound
Balancing % atom economy Ethanoic acid in vinegar
equations Mr of desired product/mr of all reactant x 100 Calcium carbonate in
High atom economy means less waste and more tablet
proftable Mr of MHCO3
Mr of succinic acid
Mass of aspirin in aspirin ta
Yield for conversion of ma
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