Fakeium has four isotopes found on Earth but they’ve only been recently discovered. Do your part as a scientist and calculate the average atomic mass for fakeium so it can be added to the periodic table. Fa - 85 is 31% of all the isotopes found.

Fa - 86 is 12% of all the isotopes found.

Fa - 87 is 38% of all the isotopes found.

Fa - 88 is 19% of all the isotopes found.

CHOICES:

84.65 g

87.00 g

87.50 g

86.45 g

86.45 g

Explanation:

Given data:

Percent abundance of Fa - 85 = 31%

Percent abundance of Fa - 86 = 12%

Percent abundance of Fa - 87 = 38%

Percent abundance of Fa - 88 = 19%

Average atomic mass of Fa = ?

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+ (abundance of 3rd isotope × its atomic mass) + (abundance of 4th isotope × its atomic mass)   / 100

Average atomic mass = (31×85)+(12×86) +(38×87)+(19×88) /100

Average atomic mass =  2635 +1032 +3306 +1672 / 100

Average atomic mass  = 8645 / 100

Average atomic mass = 86.45