- Isotopes are different atoms of the same element that contain the same number of protons and electrons but a different number of neutrons.
- These are atoms of the same elements but with different mass numbers
- Because of this, the mass of an element is given as relative atomic mass (Ar) by using the average mass of the isotopes
- The relative atomic mass of an element can be calculated by using the relative abundance values
- The relative abundance of an isotope is either given or can be read off the mass spectrum
Worked example: Calculating relative atomic mass of oxygen
The correct answer is 1
Worked example: Calculating relative atomic mass of boron