The Mystery of Iridium Isotopes

What are the naturally occurring isotopes of iridium and their relative masses?

Find the fractional abundance of Ir-191.

Answer

The naturally occurring isotopes of iridium are Ir-191 with a relative mass of 190.96058 and Ir-193 with a relative mass of 192.96292. The fractional abundance of Ir-191 is 0.372.

Iridium, a rare and precious metal, has only two naturally occurring isotopes. These isotopes, Ir-191 and Ir-193, have relative masses of 190.96058 and 192.96292 respectively.

The fractional abundance of Ir-191 can be calculated using the formula for average atomic mass:

Average atomic mass = (Atomic mass of Ir-191) x (Fractional abundance of Ir-191) + (Atomic mass of Ir-193) x (Fractional abundance of Ir-193)

By solving the equation with the given values, we find that the fractional abundance of Ir-191 is 0.372. This means that for every 100 atoms of iridium, approximately 37.2 atoms are of the Ir-191 isotope.