Chapter 1 - Atomic Structure
No description yet. This curated deck is ready for daily study.
Card preview (24)
what is the relative mass and charge on a neutron
mass: 1 charge: 0
what is the relative mass and charge of a proton
mass: 1 charge: +1
what is the relative mass and charge of an electron
mass: 1/1840 charge: -1
define relative atomic mass
the average mass of an atom of an element relative to one twelfth of the mass of an atom of carbon-12.
what must initially happen to an atom or molecule before it is put into a mass spectrometer
it must be ionised
how can atoms or molecules be ionised
using an electron gun or using electrospray ionisation
describe how the electron gun ionises atoms
en electron is shot at an atom in a high vacuum chamber the electron knocks off an electron off the atom to form a positive ion
how is electrospray ionisation carried out
a high voltage is applied to a solution with dissolved biomolecules the high voltage causes the solvent to become ionised and break into many small droplets which are small enough to be considered a gas
what conditions must be present for electron impact ionisation to be successful
there must be a high vacuum in the chamber the atom must be in a gaseous state
pros of electron impact ionisation
it can be done on individual atoms it is very powerful and effective
cons of electron impact ionisation
it’s powerful so it may cause fragmentation in biomolecules which may cause inaccuracy in the mass spectrometer reading
describe the method of mass spectroscopy
sample introduced at low pressure electron gun or electrospray used to ionise sample the sample becomes a positive ion the ions are accelerated with a negatively charged plate, then focused into a beam using a magnetic field the ions are deflected, the deflection depends on the mass to charge ratio of each ion lightest ions are deflected the most ions reach the detector where they gain an electron and produce a current which is detected the size of the current is proportional to the abundance of each isotope a mass spectrum can be produced which cab be used to calculate the Ar of the sample
what does m/z mean
mass to charge ratio
if two molecules of different mass are in one spectroscope, what about them is the same
the energy they are accelerated to is the same the distance they travel is the same the time taken to travel the distance is different the mass is different (it is usually what you are finding)
what equation can be used to find the velocity of a particle in a mass spectrometer given its distance and time taken to travel said distance
velocity = distance/time v=d/t
what equation can be used to find the mass of a sample when the velocity and energy are known
1/2mv² = KE
how many atomic orbitals are there name them in order of energy
four s, p, d, f
how many electrons can one orbital hold
2
how many electrons can the s orbital hold in total
2
how many electrons can the p orbital hold in total
6
how many electrons can the d orbital hold in total
10
how many electrons can the f orbital hold in total
14
What orbitals does the first shell contain
only 1s
What orbitals does the second shell contain
2s, 2p