atomic structure

Question 1

what is relative atomic mass?

Answer 1

the average mass of an atom of an element, relative to all isotopes, taking into account a twelfth of carbon-12

Question 2

what is relative isotopic mass?

Answer 2

the mass of an atom of an isotope of an element, relative to all isotopes, taking into account a twelfth of carbon-12.

Question 3

what is relative molecular mass?

Answer 3

the average mass of a molecule of a compound taking into account a twelfth of carbon-12.

Question 4

what 4 stages are there of mass spectrometry?

Answer 4

1) ionisation- sample is ionised
2) acceleration- positive ions are accelerated by electric field, lighter ions move faster
3) ion drift- ions enter region with no electric field
4) detection- ions reach detector, which detects the current created and records how long they took to pass

Question 5

what are the 2 different types of ionisation?

Answer 5

1) electrospray ionisation- sample is dissolved in solvent and pushed through small nozzle at high pressure, high voltage is applied so particle gains H+ ion, leaving gas of positive ions
2) electron impact ionisation- sample is vaporised and an ‘electron gun’ fires high energy electrons at it, knocking an electron off to become +1 ions

Question 6

what is a mass spectrum?

Answer 6

chart produced by a mass spec showing info about the sample that passed through