C-12 and c-13 are naturally-occurring isotopes of the element carbon. c-12 occurs 98.89% of the time and c-13 occurs 1.108% of the time. what calculation should be used to determine the atomic mass of this element?

Explanation:

You calculate the weighted average of the atomic masses.

That is, you multiply the atomic mass of each isotope by a number representing its relative importance (e.g.., its percent of the total).

Set up a table for easy calculation:

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.