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Atomic Structure
Fichas del conjunto (8)
- 15 stages of Mass Spectrometry1. Vaporisation
2. Ionisation
3. Acceleration
4. Drift
5. Detection - 2Electron Impact ionisation process and limitationsAn electron gun fires high energy electrons at the sample.
This knocks out an outer electron, forming positive ions with different charges.
Electron impact can cause fragmentation in larger compounds so is only useful with smaller Mr compounds - 3Electrospray ionisation and limitationsThe sample is dissolved in a volatile, polar solvent.
Injected through a fine needle giving a fine aerosol
The tip of needle has high voltage
At the tip of the needle the sample molecule, M, gains a proton, H+, from the solvent forming MH+
When detected the m/z value will be the Mr+1 - 4Key Electronic Configuration rules4s shell fills AND empties before 3d shell
Cr 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Cu 1s2 2s2 2p6 3s2 3p6 4s1 3d10
Half full and full subshells are the most stable so Cr and Cu have slightly different electron configuration to be more stable - 5First Ionisation energyThe energy needed to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous ions with a single positive charge
- 6Second Ionisation energy Vs First Ionisation energySecond is ALWAYS greater than the first
Removal of first electrons forms a positive ion
Ion increases its attraction to the remaining electrons so the energy required to remove the next electron is greater - 7Drop in First Ionisation energy from Mg to AlAl is starting to fill a 3p sub shell, whereas Mg has its outer electrons in the 3s sub shell. 3p electrons are higher in energy and are also slightly shielded by the 3s electrons.
- 8Drop in First Ionisation energy from P to SIn S, the electron is removed from an electron pair
Repulsion between electron pairs weakens the attraction between nucleus and the outermost electrons
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- A level (Physical Chemistry) Chemistry Fichas sobre Atomic Structure, creado por Luqman Thakor el 06/08/2020.
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- Luqman Thakor
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