Question

A new element -- quickly named Swiforskium by the scientific community -- is discovered. This element is found to have two isotopes. 86.4% of all Swidorskium atoms are Swidorskium-428 and 13.6% are Swidorskium-433. What is the atomic mass of this element? Show your work.

Answer 1

Answer: The average atomic mass of this element is 428.68 .

Step-by-step explanation:

Average atomic mass =
`\sum _(i=1)^n(\text{Atomic mass of an isotope})_i(\text{fractional abundance of an isotope})_i`

Atomic mass of Swidorskium-428 = 428

Abundance of Swidorskium-428 = 86.4%=0.864

Atomic mass of Swidorskium-433. = 433

Abundance of Swidorskium-433 = 13.6= 0.136

The atomic mass of the element is

= (atomic mass of Swidorskium-428 )(abundance) + (atomic mass of Swidorskium-433)(abundance)

The atomic mass of Swidorskium = (428)(0.864)+(433)(0.136) = 428.68