1. Mass spectroscopy – learning objectives Outline the early developments in mass spectrometry. Outline the use of mass spectrometry in the determination of relative isotopic masses and for identifying elements. Interpret mass spectra of elements in terms of isotopic abundances. Keywords: mass spectroscopy, fragmentation, m/z, isotope

2. History of mass spectroscopy

3. Uses of mass spectroscopy

4. How a mass spectrometer works

6. Mass spectra of elements

7. Key features of the spectrum There are 3 peaks in the spectrum, so there are 3 isotopes of magnesium The heights of the peaks give the relative abundance of the isotope in the sample The results can be used to find the relative atomic mass The spectrum tells us that: 73.4% is magnesium-24, 12.7% is magnesium-25, 13.9% is magnesium-26 RAM = (24x73.4) + (25x12.7) + (26x13.9) = 24.41 100

8. How many isotopes? What is the relative atomic mass? How many isotopes? What is the relative atomic mass?