Are relative atomic masses of elements whole numbers ?

Asked by Aditya Chaturvedi chaturvedi | 31st Dec, 2013, 12:43: PM

Expert Answer:

The naturally occurring elements such as chlorine often consist of a mixture of isotopes. These results in relative atomic mass of an element which represents the average mass of one atom of that element, taking into account the different isotopes and their relative proportions.

For example, chlorine consists of two isotopes 35Cl and 37Cl. When pure 35Cl is present then the relative atomic mass is 35 or when pure 37Cl is present, then relative atomic mass is 37. But it rarely occurs that 100% pure compound is present.

If there is 75% 35Cl and 25% 37Cl is present, then relative atomic mass of chlorine is

=  (35 x 75/100) + (37 x 25/100)

=  26.25 + 9.25

= 35.50

 Hence, relative atomic masses are not rarely whole numbers.

 

Answered by Prachi Sawant | 2nd Jan, 2014, 04:09: PM

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