Specification Point 1.17:
Be able to calculate the relative atomic mass of an element (Ar) from isotopic abundances
Calculating Relative Atomic Mass
Atoms of the same element that contains the same number of protons and electrons but different number of neutrons.
(% of isotope 1 x mass of isotope 1) + (% of isotope 2 x mass of isotope 2)
Ar = _______________________________________________________________
The table shows information about the isotopes in a sample of Rubidium
|Isotope||Number of protons||Number of neutrons||Percentage of isotope in sample|
Use information from the table to calculate the relative atomic mass of this sample of Rubidium. Give your answer to one decimal place.
( 72 x 85 ) + ( 28 x 87 )
____________________________ = 85.6
Relative atomic mass = 85.6
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