Question

Indium possesses two naturally occurring isotopes, In-113 and In-115. The abundance and atomic mass of these isotopes is: In-113, 4.29% and 112.904; In-115, 95.71% and 114.904. Which is the average atomic mass of indium? Group of answer choices 114.818 112.999 114.904 113.904

Answer 1

option A.

Step-by-step explanation:

given,

The abundance and atomic mass of In-113 is 4.29 % and 112.904

The abundance and atomic mass of In-115 is 95.71 % and 114.904

Average atomic mass =
`\sum(isotope\ mass * abundance\ of\ isotope)/(100)`

Average atomic mass =
`(4.29* 112.904+95.71* 114.904)/(100)`

=
`(4.29* 112.904+95.71* 114.904)/(100)`

= 114.818

the average atomic mass comes out to be 114.818

hence, the correct answer is option A.