AQA A LEVEL CHEMISTRY PAPER 1 Study Guide
Rated A+
1). Tof steps
Ans: 1) ionisation
2) acceleration
3) ion drift
4) detection
5) analysis
2). Electron impact
Ans: Sample vaporised and electron gun fires high energy electrons at it which knock
off 1 electron from each particle, making them 1+ ions
NB- can knock off more than one e or break molecular ion
3). Electrospray ionization
Ans: Sample dissolved in volatile solvent then injected through needle to give fine mist
which is attached to positive end of high voltage power supply, particles gain proton
NB- Mr of substance is actually one less than shown due to extra H+
4). Acceleration (tof)
Ans: positive ions accelerated using electric field so they all have the same kinetic
energy
5). Ion drift (tof)
Ans: particles with small mass have larger velocity do ions start to separate with
lightest ions reaching detector first
6). Detection (tof)
Ans: positive ions hit negatively charged plate and gain an electron which forms a
current, the larger the current the higher the abundance
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, 7). Analysis (tof)
Ans: -computer uses data to produce mass spectrum which shows mass m / charge z
ratio
-mr or ar is furthest right peak (small peaks larger than mr are due to isotopes)
-may be large peaks at lower mr due to fragmentation
8). Electron spin
Ans: Property of electron (CW or ACW)
Represented by up and down arrows
9). Orbitals
Ans: Defined regions of space around nucleus where electrons most likely to be found,
each orbital holds 2 electrons
10). Hund's rule
Ans: Electrons prefer to occupy orbitals on their own and only pair up when no empty
or bait ask of same energy are available
11). Electron configuration
Ans: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10
12). Exceptions to electron configuration
Ans: chromium and copper, only take one electron in 4s orbital
13). Why does ionization energy decrease down a group?
Ans: Atoms get bigger so electrons further away from nucleus, greater shielding
14). Why does ionization energy increase across a period?
Ans: Atoms get smaller, nuclear charge increases, similar shielding
15). Dip in ionisation energy groups 2-3
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Rated A+
1). Tof steps
Ans: 1) ionisation
2) acceleration
3) ion drift
4) detection
5) analysis
2). Electron impact
Ans: Sample vaporised and electron gun fires high energy electrons at it which knock
off 1 electron from each particle, making them 1+ ions
NB- can knock off more than one e or break molecular ion
3). Electrospray ionization
Ans: Sample dissolved in volatile solvent then injected through needle to give fine mist
which is attached to positive end of high voltage power supply, particles gain proton
NB- Mr of substance is actually one less than shown due to extra H+
4). Acceleration (tof)
Ans: positive ions accelerated using electric field so they all have the same kinetic
energy
5). Ion drift (tof)
Ans: particles with small mass have larger velocity do ions start to separate with
lightest ions reaching detector first
6). Detection (tof)
Ans: positive ions hit negatively charged plate and gain an electron which forms a
current, the larger the current the higher the abundance
PaperStoc.com Page 1 of 11
, 7). Analysis (tof)
Ans: -computer uses data to produce mass spectrum which shows mass m / charge z
ratio
-mr or ar is furthest right peak (small peaks larger than mr are due to isotopes)
-may be large peaks at lower mr due to fragmentation
8). Electron spin
Ans: Property of electron (CW or ACW)
Represented by up and down arrows
9). Orbitals
Ans: Defined regions of space around nucleus where electrons most likely to be found,
each orbital holds 2 electrons
10). Hund's rule
Ans: Electrons prefer to occupy orbitals on their own and only pair up when no empty
or bait ask of same energy are available
11). Electron configuration
Ans: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10
12). Exceptions to electron configuration
Ans: chromium and copper, only take one electron in 4s orbital
13). Why does ionization energy decrease down a group?
Ans: Atoms get bigger so electrons further away from nucleus, greater shielding
14). Why does ionization energy increase across a period?
Ans: Atoms get smaller, nuclear charge increases, similar shielding
15). Dip in ionisation energy groups 2-3
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