chemistry - unit 1

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  • Created by: Monica
  • Created on: 17-05-13 19:59
what is the relative mass of a proton, neutron, and electron?
proton: 1 neutron: 1 electron: 1/2000
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what is the relative charge of a proton, neutron and electron?
proton: +1 neutron: 0 electron: -1
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what is the mass number on a atom?
the top number, it tells you the total number of protons and neutrons in the nucleus.
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what is the atomic number on a atom?
the bottom number it tells you how many protons(electrons) are in the nucleus.
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what is an isotope?
atoms with the same number of protons but different number of neutrons.
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MASS SPECTROMETER - what happens at vaporsation?
the sample is turned into a gas (vaporised) using an electrical heater.
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MASS SPECTROMETER - what happens at ionisation?
the gas particles are bombarded with high energy electrons. electrons are knocked off the particles leaving positive ions.
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MASS SPECTROMETER - what happens at acceleration?
the positive ions are accelerated by an ELECTRIC FIELD.
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MASS SPECTROMETER - what happens at deflection?
the positive ions pathways are altered by the MAGNETIC FIELD, lighter ions have less momentum and are deflected MORE than heavier ions. only ions with a particular mass/charge make it to the detector.
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MASS SPECTROMETER - what happens at detection?
the magnetic fields strength is slowly increased, as this happens the different ions (with a higher mass/charge ratio) can reach the detector, and a mass spectrum is produced.
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MASS SPECTRUM - whats on the y-axis?
abundance of ions - % abundance or relative abundance
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MASS SPECTRUM - whats on the x-axis?
mass/charge (mass over charge)
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WORKING OUT MASS SPECTRUM - how do you work out the Ar?
times the top peak by the mass/charge number, add up all the answers and divide by 100. IF IT ISNT A PECENTAGE DIVIDE BY THE TOTAL RELATIVE ABUNDANCE.
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ELECTRONIC STRUCTURE - what is the order of the sub shells?
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 4d10, 4f14
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Name two ways in which transition metals behave differently?
1)chromium and copper donate one of there 4s subshells to the 3d subshell because they're more happier with a more stable or half full 3d subshell. 2)when transition metals become ions they lose their 4s electrons before they lose their 3d electrons
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chemical properties of s block elements group 1 and 2...
they have 1 or 2 outer shell electrons these are easily lost to form positive ions with a inert gas configuration.
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chemical properties of elements in group 5, 6, 7 'p' block...
can gain 1, 2 or 3 electrons to form negative ions with an inert gas configuration.
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chemical properties of group 0 (the inert gases)...
there s and p subshells dont need to lose or gain any electrons there full subshells make them inert.
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chemical properties of the 'd' block elements (transition metals)...
they tend to lose their s and d electrons to form postivie ions.
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IONISATION ENERGIES - what is the first ionisation energy?
the first ionisation energy is the energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.
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what is the equation for the first ionisation of oxygen?
o(g) --> o+(g) + e-
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trend in ionisation energy?
the lower the ionisation energy the easier it is to form an ion.
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how does nucleur charge affect ionisation energy?
the more protons there are in the nucleus the more positivley charged the nucleus is and the stronger the attraction for the electrons.
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how does the distance from the nucleus affect the ionisation energy?
attraction falls off very rapidly with distance. an electron close to the nucleus will be more strongly attached than one further away
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how does the amount of shells affect the ionisation energy?
the more shells there are the further the outermost electons are from the nucleus, electrons from the inner shells repel electons in the outer shells and reduce the affect of the positive nucleus, more shielding=its easier to remove the electron
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structure of metallic bonding
consist of a lattice of positive ions in a sea of delocalised electrons
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what makes metals good conductors of ELECTRICITY
the delocalised electrons can move throughout the structure
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what makes metals good conductors of HEAT
energy is spread by increasingly vigorous vibrations of the closely packed ions
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What is the sructure of diamond
atoms form a giant 3D lattice of strong covalent bonds, very hard, very high melting point
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structure of graphite
each carbon atom forms 3 single covalent bonds to other carbon atoms, trigonal planar, 120 angle, bonds are held together by van der waals, soft, hight melting point, layers can slide-soft and flaky
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ionic bonding - bonds between two oppositly charged ions
between groups 1&2 and 6&7, electrostatic force of attraction
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why do metals have low ionisation energies
can lose electrons easily form positive ions
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why do non-metals have high electron affinities
gain electrons easily to form negative ions
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Other cards in this set

Card 2

Front

what is the relative charge of a proton, neutron and electron?

Back

proton: +1 neutron: 0 electron: -1

Card 3

Front

what is the mass number on a atom?

Back

Preview of the front of card 3

Card 4

Front

what is the atomic number on a atom?

Back

Preview of the front of card 4

Card 5

Front

what is an isotope?

Back

Preview of the front of card 5
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