Atomic structure

what are isotopes
Isotopes are atoms with the same number of protons but a different number of neutrons
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why does a mass spectrometer need to be done under vacuum
To stop ions colliding with the air
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what is electron impact
sample injected in at low pressure, electron gun fires high energy electrons at sample, knocks out outer electron forming a sample with a positive charge
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what is electrospray ionisation
sample dissolved in a volatile solvent,injected through a fine hollow needle,the needle has a high voltage, sample molecule gains a proton, ion moves to charged plate
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what is the acceleration stage of the mass spectrometer
positive ions are accelerated by an electric field, kinetic energy isconstant
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what happens in the flight tube in the mass spectrometer
positive ions with smaller m/z values will have the same kinetic energy as larger ones and get there faster,heavier particles take longer to move through the drift area.
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what happens at the detection stage of the mass spectrometer
The ions reach the detector and generate a small current which is fed to a computer for analysis, current is produced by electrons transferring from the detector to the positive ions,
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how do you calculate relative atomic mass
isotopic mass x abundance/100
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how do you work out relative atomic mass if you relative atomic abundance instead
(isotopic mass x relative abundance) /total relative abundance
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how many electrons does an S orbital hold
2
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how many electrons does a P orbital hold
6
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how many electrons does a D orbital hold
10
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How many electrons does an F orbital hold
14
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What is the first ionisation energy
The amount of energy needed to remove one mole of electrons from one mole of gaseous atoms
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what is the second ionisation energy
the amount of energy needed to remove a second electron from each ion in 1 mole of gaseous ions
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what are the three factors affecting ionisation energy
the nuclear charge,the atomic radius,the electron shielding
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why is more energy required to remove the second electron than the first
the ion increases the attraction on the remaining electrons
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why does helium have the largest first ionisation energy
Its first electron is in its first shell closest to the nucleus and has no shielding
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why does ionisation energy decrease down a group
AS you go further down a group the electrons get more shielding so less attraction to nucleus
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why does Na have a lower ionisation energy than neon
Has its outer electrons in a 3s orbital and there is more shielding
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why is there a small drop in ionisation energy from Mg to Al
Al has electrons in the 3p orbital whereas magnesium in the 3s orbital the electrons in 3p are easier to remove as they are higher in energy
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why is there a small drop in ionisation energy from P to S
4 electrons in sulphur 3p orbital when the second electron is added there is slight repulsion between two negatively charged electrons
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Other cards in this set

Card 2

Front

why does a mass spectrometer need to be done under vacuum

Back

To stop ions colliding with the air

Card 3

Front

what is electron impact

Back

Preview of the front of card 3

Card 4

Front

what is electrospray ionisation

Back

Preview of the front of card 4

Card 5

Front

what is the acceleration stage of the mass spectrometer

Back

Preview of the front of card 5
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