If you had a sample of natural carbon containing exactly 10,000 atoms, determine the number of 12c and 13c atoms present.

Carbon 12 and carbon 13 are two naturally occurring isotopes of the element.  Carbon 12 accounts for approximately 98.9 percent of naturally occurring carbon while carbon 13 accounts for approximately 1.1 percent. Therefore if a sample has 10,000 atoms, 9890 atoms would be carbon 12 and 110 atoms would be carbon 13. 

Noble gases is far right