If the abundance of 85 Rb is 72.2% and the abundance of 87 Rb is 27.8%, what is the average atomic mass of rubidium?

The average atomic mass of Rubidium : 85.556 u

Isotopes are atoms that have the same atomic number but different mass numbers

Each isotope has an abundance which is usually expressed as a percentage

The average relative mass of atoms is obtained by adding the product of the percentage and mass of each isotope

Can be formulated:

The abundance of 85 Rb is 72.2% and the abundance of 87 Rb is 27.8%, so

mass isotope 1=85, %abundance=72.2

mass isotope 2=87, %abundance=27.8

The averages atomic mass of Rubidium :

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.