AQA A LEVEL CHEMISTRY PAPER 1 COMPLETE EXAM
REVIEW | VERIFIED & UPDATED 2025–2026
TOF steps - correct answer -1) ionisation
2) acceleration
3) ion drift
4) detection
5) analysis
Electron impact - correct answer -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
electrospray ionization - correct answer -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+
Acceleration (TOF) - correct answer -positive ions accelerated using electric field so they all
have the same kinetic energy
Ion drift (TOF) - correct answer -particles with small mass have larger velocity do ions start to
separate with lightest ions reaching detector first
Detection (TOF) - correct answer -positive ions hit negatively charged plate and gain an electron
which forms a current, the larger the current the higher the abundance
Analysis (TOF) - correct answer --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
Electron spin - correct answer -Property of electron (CW or ACW)
Represented by up and down arrows
Orbitals - correct answer -Defined regions of space around nucleus where electrons most likely
to be found, each orbital holds 2 electrons
Hund's Rule - correct answer -Electrons prefer to occupy orbitals on their own and only pair up
when no empty or bait ask of same energy are available
Electron configuration - correct answer -1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10
exceptions to electron configuration - correct answer -chromium and copper, only take one
electron in 4s orbital
Why does ionization energy decrease down a group? - correct answer -Atoms get bigger so
electrons further away from nucleus, greater shielding
Why does ionization energy increase across a period? - correct answer -Atoms get smaller,
nuclear charge increases, similar shielding
Dip in ionisation energy groups 2-3 - correct answer -Electrons take up higher orbital (s to p)
which makes ionisation energy lower as higher orbitals have higher energy
Dip in ionisation energy groups 5-6 - correct answer -Electron- electron repulsion in orbital
makes electron easier to lose
REVIEW | VERIFIED & UPDATED 2025–2026
TOF steps - correct answer -1) ionisation
2) acceleration
3) ion drift
4) detection
5) analysis
Electron impact - correct answer -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
electrospray ionization - correct answer -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+
Acceleration (TOF) - correct answer -positive ions accelerated using electric field so they all
have the same kinetic energy
Ion drift (TOF) - correct answer -particles with small mass have larger velocity do ions start to
separate with lightest ions reaching detector first
Detection (TOF) - correct answer -positive ions hit negatively charged plate and gain an electron
which forms a current, the larger the current the higher the abundance
Analysis (TOF) - correct answer --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
Electron spin - correct answer -Property of electron (CW or ACW)
Represented by up and down arrows
Orbitals - correct answer -Defined regions of space around nucleus where electrons most likely
to be found, each orbital holds 2 electrons
Hund's Rule - correct answer -Electrons prefer to occupy orbitals on their own and only pair up
when no empty or bait ask of same energy are available
Electron configuration - correct answer -1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10
exceptions to electron configuration - correct answer -chromium and copper, only take one
electron in 4s orbital
Why does ionization energy decrease down a group? - correct answer -Atoms get bigger so
electrons further away from nucleus, greater shielding
Why does ionization energy increase across a period? - correct answer -Atoms get smaller,
nuclear charge increases, similar shielding
Dip in ionisation energy groups 2-3 - correct answer -Electrons take up higher orbital (s to p)
which makes ionisation energy lower as higher orbitals have higher energy
Dip in ionisation energy groups 5-6 - correct answer -Electron- electron repulsion in orbital
makes electron easier to lose
