Criado por keirancorbett
mais de 10 anos atrás
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Copiado para Nota por keirancorbett
mais de 10 anos atrás
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PEN Proton Electron Neutron Mass number = proton + neutrons In atom P=E Isotope Charge = +1 Relative mass = 1 Charge = -1 Relative mass = 0 No charge Relative mass = 1 Different number of neutrons Chemical properties depend on electrons same proton number Electrons arranged same in isotope so same chemical properties Physicals properties differ slightly because mass changes
Mass Spectrometer VIADD m/z on x axis Abundance (usually %) on y Vapourisation Ionisation Acceleration Deflection Detection Electron gun fires high energy electrons He(g) --> He+ (g) + e- But use minimum as want least 2+ ions Some 2+ ions created Mg+(g) + e- --> Mg2+ (g) +2e- Negative plates attract +ions which accelerates Electromagnet produces variable magnetic field Amount deflected depends on m/z mass/charge Larger m/z the smaller the deflection 24Na+ and 48Ti2+ Same m/z ratio 48/2 and 24/1 = 24 So deflected by same amount Tiny current is produced as ion takes electron from negative plante This is then amplified and sent to computer More currents = higher peak current depends on number of ions From graph can calculate relative atomic mass (Ar) Ar=((% x m/z) + (% x m/z) +.....)/total % Ar = average mass of one atom of an element / 1/12 the mass of one carbon-12 atom Mr = average mass of one molecule/ 1/12 the mass of one carbon-12 atom
Electronic configuration Orbitals Ionisation Energies 1s 2s 2p 3s 3p Examples 4s filled befoe 3d electrons are paired with opposite spin with p and greater orbitals electrons remain unpaired filling empty orbitals first but with parallel spin Na 1s2 2s2 2p6 3s1 Ti 1s2 2s2 2p6 3s2 3p6 3d2 4s2 Exceptions Cr 1s2 2s2 2p6 3s2 3p6 3d5 4s1 Cu 1s2 2s2 2p6 3s2 3p6 3d10 4s1 Increases Across period 3 Decreases down Group 2 Second ionisation energy always higher Proton number increase Shielding stays the same Atoms become smaller as you go across Exceptions (Decreases) Aluminium - further from nucleus as it is first element with 3p electron Sulfur - first paired 3p electron so decrease due to electron-electron repulsion More shielding as you go down (offsets proton increases) Further from nucleus less shielding lost from ion Ion is smaller
Atomic Structure
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