Mass Spectrometry
Mass spectrometry separates positive ions according to their mass-to-charge ratio, written as m/z. These pages build from the operation of the mass spectrometer through to isotope abundance, relative atomic mass and interpreting molecular spectra.
These pages cover atomic structure, isotopes and the four mass spectrometry pages. Relative molecular and formula mass are used throughout the Amount of Substance pages.
Revision Notes
4 revision notes, in the order the specification teaches them.
The Mass Spectrometer
Revise vaporisation, ionisation, acceleration, deflection, detection and why ions are separated by m/z.
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RAM Calculations
Use isotopic mass and percentage abundance data to calculate relative atomic mass using weighted means.
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Predicting Diatomic Mass Spectra
Predict molecular ion peak patterns for diatomic molecules using isotope combinations and probability ratios.
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Identifying Compounds from Mass Spectra
Use the molecular ion peak, the M+1 peak and simple fragment peaks to find the relative molecular mass and identify an unknown compound.
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Summary map
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Atomic Structure and Isotopes Map
OCR A Level Chemistry A · 2.1.1 Atomic structure and isotopes
The whole of 2.1.1 on one A4 page: sub-atomic particles, isotopes, mass spectrometry, the carbon-12 scale, and M_r and relative formula mass.
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2.1.1
- c i
explanation of the term relative isotopic mass (mass compared with 1/12th mass of carbon-12), based on the mass of a 12C atom, the standard for atomic masses
Revise - c ii
explanation of the term relative atomic mass (weighted mean mass compared with 1/12th mass of carbon-12), based on the mass of a 12C atom, the standard for atomic masses
Revise - d (ii)
use of mass spectrometry in the calculation of the relative atomic mass of an element from the relative abundances of its isotopes
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4.2.4
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