atomic structure

what are protons + neutrons held together by?

strong nuclear force

what is carbon dating?

all things absorb carbon from atmosphere
its age can determined by the amount of C14 they contain after dying when they have stopped absorbing

what is the arrangement of electrons in shells?

2,8,18,32

relative atomic/molecular mass?

1/12 mass of 1 atom/molecule of C12

electron impact ionisation?

sample vaporised
fired at with electron gun, which knocks off an e-
+ion formed

electron impact acceleration?

+ions accelerate towards negatively charged plate due to attraction

how does mass/charge affect ion acceleration?

lighter/more charged ions travel faster

electron impact ion drift?

ions pass through hole in negatively charged plate
forming a beam along the tube to the detector

electron impact detection?

flight times recorded
+ions pick up e-, creating a current

electron impact data analysis?

signal from detector passed to computer

electrospray ionisation?

sample dissolved in volatile solvent
forced through fine needle connected to a high voltage supply
forms fine mist/aerosol
droplets gain proton from solvent - form +ions
solvent evaporates from droplets into vacuum
drops get smaller until they can only contain 1 +ion

calculate average Ar from mass spec graph?

(mass/charge ratio x abundance)

total abundance

calculate average mass of isotopes?

(mass no. x isotope %) of each isotope

100

how many electrons can be held in each orbital?

s - 2
p - 6
d - 10
f - 14

how are the orbitals filled?

1s², 2s², 2p⁶, 3s²,3p⁶, , 4s²

→ 4s orbital is filled before 3d

how are electrons in the same orbital w/ opposite spin drawn?

drawn 2 at a time

what is ionisation energy?

energy required to remove 1 e- from a mole of atoms to form a mole of +ions as a gas

why does the second IE req. more energy?

as it is from a +1 atom, not a neutral one
so the electrons are more strongly attracted to the positive charge

how does IE change within the periodic table?

increases across a period
decreases down a group

why is the first IE the easiest?

furthest from the nucleus
inner electrons shield it from the positive centre, weakening attractive forces

what does the s orbital look like?

what does the p orbital look like?

why is alumium’s IE less than magnesium’s, when it should be higher?

less energy req
as e- is being removed from 3p orbital, which is further away from the nucleus