• 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

Answer

The correct answer is?1

= 16.0044

= 16.00

Worked example: Calculating relative atomic mass of boron

Answer