If you had a bag with 200 atoms of Krypton in it, how many of them would be Krypton-83?

23 atoms

Explanation:

Krypton (Kr) exists naturally as a mixture of six isotopes with atomic number of 36. These six isotopes occupy different percentages of the mixture. Below is a list of the isotopes and there percentage in a given mixture

1) Krypton-78 (⁷⁸Kr) ⇒ 0.35%

2) Krypton-80 (⁸⁰Kr) ⇒ 2.25%

3) Krypton-82 (⁸²Kr) ⇒ 11.6%

4) Krypton-83 (⁸³Kr) ⇒ 11.5%

5) Krypton-84 (⁸⁴Kr) ⇒ 57%

6) Krypton-86 (⁸⁶Kr) ⇒ 17.3%

To determine the amount of ⁸³Kr present in a mixture of 200 atoms of krypton, you will multiply the it's percentage of occurrence in nature by the amount of atoms in a given mixture

11.5/100 × 200 = 23 atoms

Hence, there should be 23 atoms of krypton-83 in the mixture of 200 atoms of Krypton.