atomic structure
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atomic number
amount of protons
what expression gives mass number
proton number plus neutron number
expression for proton number
mass number- neutron number
expression for neutron number
mass number - proton number
whats mass number
neutron number plus proton number
atomic mass unit
measures weight of atoms 1/12 of carbon 12
how to calculate relative mass
take isotope and times relative abundance by atomic mass add together and divide by 100
symbol for relative atomic mass
Ar
whats the relative atomic mass definition
the average mass of one atom of an element relative to one twelfth of the mass of carbon 12
kinetic energy equation
0.5 times mass times velocity squared
unit for kinetic energy
Joules
unit for mass in kinetic energy
kg
rearranged kinetic energy equation for mass
m= 2ke/v squared
rearranged equation of kinetic energy for speed
v= square root 2ke/m
time of flight
distance travelled by atom to calculate its mass
equation for atoms mass from time of flight
m=2ke times t squared/distance aquared
rearranging time of flight formula for time subject
t= root distance root m/2ke
time of flight mass equation for distance subject
d= root t times root 2ke/m
why do we turn atoms into ions in time of flight
because atoms nuetral they need charge to be attracted to charged metal plate
what do we need to do so charged plate can give atoms kinetic energy
ionise them
whats a time of flight mass spectrometer
measures time of flight of atom to work our mass of atom
4 steps of mass spectrometry
-ionisation -acceleration -ion drift -detection
electron gun ionisation
hot wire that emits electric current which emits fast moving electrons and knocks electron of atom and makes positive charged atom
vaporisation
to get atoms ready for electron gun they are heated to get ready for electron gun