AQA A LEVEL CHEMISTRY PAPER 1 Exam Questions and Answers

TOF steps 1) ionisation 2) acceleration 3) ion drift 4) detection 5) analysis Electron impact 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 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) positive ions accelerated using electric field so they all have the same kinetic energy Ion drift (TOF) particles with small mass have larger velocity do ions start to separate with lightest ions reaching detector first Detection (TOF) positive ions hit negatively charged plate and gain an electron which forms a current, the larger the current the higher the abundance Analysis (TOF) -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 Property of electron (CW or ACW) Represented by up and down arrows Orbitals Defined regions of space around nucleus where electrons most likely to be found, each orbital holds 2 electrons Hund's Rule 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 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10