Atomic Structure (INCLUDING TOF AND IONISATION ENERGY)
- Created by: ZoeKing98
- Created on: 04-05-16 19:31
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- Atomic Structure
- Sub-atomic particles
- Electron
- -1 charge (relative)
- Mass of 1/1840 (relative)
- Found in shells/orbitals surrounding the nucleus
- Neutron
- 0 charge (relative)
- Mass of 1 (relative)
- Found by minusing atomic number from mass number
- Proton
- +1 charge (relative)
- Mass of 1 (relative)
- Found in nucleus (nucleon)
- Neutron
- 0 charge (relative)
- Mass of 1 (relative)
- Found by minusing atomic number from mass number
- Neutron
- Represented by atomic number
- Electron
- Isotopes
- Atoms of same element with varying numbers of neutrons
- Same electron configuation
- Same chemical properties
- Same electron configuation
- Atoms of same element with varying numbers of neutrons
- Electron shells
- First holds up to 2 electrons
- Second holds up to 8 electrons
- Third holds up to 18 electrons
- Divided into orbitals
- s-orbital
- spherical in shape
- Holds up to 2 electrons
- p-orbitals
- Come in threes
- Each one of the three can hold up to two electrons - 6 in total
- Dumbell shaped
- d-orbitals
- Come in groups of 5
- Shorter/fatter dumbell shaped and doughnut shaped
- Each of five holds up to 2 electons - 10 in total
- Areas where the probability of finding an electron is the highest (95%)
- Electrons fill orbitals singularly first then pair
- Spin - the pair spin in opposite directions to overcome repulsion
- s-orbital
- TOF Mass Spectrometry
- High resolution
- Five decimal places
- Low resolution
- One decimal place
- Step 1: ionisation
- Electrospray ionisation - sample dissolved in volatile substance and injected through hypodermic needle where the tip is attached to a positive terminal of high voltage supply, particles ionised by gaining a proton
- Electron impact - sample vapourised an electrons fired at it from an electron gun which knocks off electrons
- Step 2: acceleration
- Accelarted towards a negatvey charged plate through an electric field to give all ions the same kinetc energy, lighter particles having a higher velocity and travelling faster
- Stage 4: detection
- Ions hit a negatively charged plate, discharged by gaining electrons and a measurable current- the size of the current determining the bumber of ions hitting the plate
- Mass spectrum
- Shows isotopes
- Shows fragments
- Peak shows relative abundance
- Tallest and furthest far right signal - molecular ion
- High resolution
- Ionisation energy (IE)
- First ionisation: The energy required to remove a mole of electrons from one mole of atoms in gaseous state to form 1+ ions
- Second/successive: The energy required to removed a mole of electrons from one mole of n+ ions in gaseous state to form n+1+ ions
- Xn+(g) ------ Xn+1+(g) + e-
- Measured in kJmol-1
- Second/successive: The energy required to removed a mole of electrons from one mole of n+ ions in gaseous state to form n+1+ ions
- Xn+(g) ------ Xn+1+(g) + e-
- Second/successive: The energy required to removed a mole of electrons from one mole of n+ ions in gaseous state to form n+1+ ions
- X(g) --------- X + (g) + e-
- Second/successive: The energy required to removed a mole of electrons from one mole of n+ ions in gaseous state to form n+1+ ions
- Trends
- Across a period
- Generally increases due to higher nuclear charge
- Exceptions include moving to a new orbital or when electrons begin to pair within them to cause a decrease
- Generally increases due to higher nuclear charge
- Down a group
- Generally decreases due to more sheilding and further distance from nucleus
- Across a period
- First ionisation: The energy required to remove a mole of electrons from one mole of atoms in gaseous state to form 1+ ions
- Sub-atomic particles
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