Question

The atomic weight of an unknown element,in atomic mass units (amu),is approximately 20% less than that of calcium. The atomic weight of calcium is 40 amu. What is the approximate weight,in amu,of the unknown element?

Answer 1

amu of unknown element = 40 - (20% * 40)
= 40 - 8
= 38 amu

therefore, the approximate weight of the unknown element is 38 amu.

hope this helps.