Elements and the periodic table
Nanoparticles:
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Usually spherical with a diameter of 1-100 nanometres (10-9 meters)
Used in:
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They have a very surface area to volume ratio, which is important for:
i.
ii.
iii.
i.
ii.
iii.

Chemotherapy
Sunscreens
Industrial catalysts
Absorption of molecules (ie: can be used to remove chemicals and unwanted waste in
industrial applications).
Transport of molecules that are absorbed into the nanoparticle (ie: into the body for
medicine).
Catalysing, as their surfaces can be used to increase the rate of chemical reactions
(reactants absorb onto the surface of the nanoparticle and react).
When a substance is processed into a nanoparticle, its physical, chemical and optical
properties can change such as gold, which looses its lustre.
Elements:
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Simplest substances that cannot be broken down using chemical reactions.
Same atomic number and number of protons (isotopes of elements- mass number
changes).
MN: number of Protons +
Neutrons
AN: Number of Protons
and electrons
Atomic models:

Dalton:
i.
Believed that all atoms were the same and that they were the simplest form of matter
that could not be broken down any further.
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Thompson:
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Rutherford:
i.
i.
ii.

Bohr:
i.
ii.
iii.
Plum pudding model- believed that atoms were spheres of positive charge (the pudding)
with small blobs (raisins) of negative charges within them.
Believed that an atom consisted of a positive nucleus surrounded by negative ‘clouds’ of
negatively charged electrons.
Conducted the gold foil experiment.
Expanded on Rutherford’s model, proposing that electrons only occupy certain orbitals
around an atom and don’t just move randomly around.
He proved his theory by discovering the different frequencies of light emitted by certain
atoms and devised the emission spectra.
Proved that electrons emit light energy when they jump to lower energy levels.
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Schrodinger:
i.
ii.
Took the Bohr model further by mathematically predicting the probability of finding an
electron in a certain position at a certain time.
Proved that atoms do not move in fixed orbits as Bohr suggested, but only move in places
whose probable location can be calculated.
Schrodinger’s quantum model
SPDF notation of atoms:
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Way of describing the electron configuration of an atom.
2 electrons to S subshells (1 orbital holding 2 electrons)
6 electrons to P subshells (3 orbitals holding 2 electrons each)
10 electrons to D subshells (5 orbitals holding 2 electrons each)
14 electrons to F subshells (7 orbitals holding 2 electrons each)
Exceptions: Copper (Cu) and Chromium (Cr) (4s is preceded by 3d, which is filled until
there is one more electron left for 4s at the end).
Condensed formula: place noble gas in the row before in brackets and then continue
the configuration of electrons from thee until you reach that of your element.