Relative atomic mass

• Relative atomic mass


  The weighted average of the mass numbers of an element's isotopes, based on their abundance
• Calculating relative atomic mass

  1. Mass number of isotope 1 x percent abundance of isotope 1

  2. + Mass number of isotope 2 x percent abundance of isotope 2

  3. / 100
• Relative atomic mass of boron calculated using the formula is 10.8
• Relative atomic mass of boron on the periodic table is rounded up to 11
• Relative atomic mass of magnesium calculated using the formula is 24.3
• Relative atomic mass of magnesium on the periodic table is rounded down to 24