atoms, ions and compounds

Question 1

what are isotopes?

Answer 1

atoms of the same element with different numbers of neutrons and different masses

Question 2

what is relative isotopic mass?

Answer 2

the mass of an isotope relative to 1/12 of carbon-12

Question 3

what is relative atomic mass?

Answer 3

the weighted mean mass of an atom of the element relative to 1/12 carbon-12

Question 4

how would one use a mass spectrometer?

Answer 4

1. place sample in the MS
2. vaporise using heat
3. bombard it with high-energy electrons (ionisation)
4. accelerate the ions towards the magnetic sector
5. the ions are deflected and then detected on a mass:charge ratio (m/z)

Question 5

how are the isotopes detected in a mass spectrometer?

Answer 5

1. heavier ions move more slowly and are harder to deflect than lighter ions
2. m/z = relative mass of ion/relative charge on ion
3. each ion detected adds to its respective signal so abundances can be calculated