Question

The element boron consists of two isotopes boron atomic number is 5 and mass number is 10 and boron atomic number 5 mass number 11.thier masses based on the carbon scale are 10.01 and 11.01 respectively.the abundance of b atomic number5 mass number 10 is 20.0% and the abundance of boron atomic number 5 mass number 11 is 80.0%.what is the atomic mass of boron

Answer 1

Explanation:

The percentages of multiple isotopes must add up to 100%.

atomic mass = (atomic mass X1) × (% of X1)/100 + (atomic mass X2) × (% of X2)/100

Substituting for boron in this equation:

atomic mass of B = 10.01 × 20.0/100 + 11.01 × 80.0/100

atomic mass of B = 2.00 + 8.81

atomic mass of B = 10.81