An element X have three isotopes X ^20 ,X ^21 and X ^22 . The percentage abundance of X^20 is 90% and the average atomic mass of element is 20.18. The percentage abundance of X ^21 should be

 Answer Key: 2%

Calculate Average atomic mass of Argon the natural abundance % of isotopes of Argon is given as:

Answer Key: 39.94 amu

Calculate the average atomic mass of silicon if relative abundance is 92.23 ,isotope Si^28, 4.77 % isotope = Si^29 and 3% isotope = Si^39 .

Answer Key: The average atomic mass of silicon is 28.1 amu

Silver contains two isotopes Ag 107 and Ag109 and average atomic weight of silver is 108.5 find percentage abundant of isotopes of silver.

 Answer Key: Ag (107) 25% and Ag (109) 75%

Boron have two isotopes B11 and BA and their relative abundant % are 80% and 20% respectively and average atomic weight of Boron is 10.8 find the value of “A”

 Answer Key:  A= 10