Element x has two isotopes. the table gives information about these isotopes. isotope atomic mass (amu) abundance (%) x-63 62.9296 69.15 x-65 64.9278 30.85 the average atomic mass of element x is amu.

The average atomic mass of element X is 63.545 amu.

Explanation:

The average atomic mass is can be calculated by the summation of the product of the atomic mass of each isotope multiplied by its abundance (abundance % / 100.0)

Element X has two isotopes:

1) At.mass = 62.9296 amu and its abundance = 0.6915

2) At.mass = 64.9278 amu and its abundance = 0.3085

The average atomic mass of element X = (62.9296 amu)*(0.6915) + (64.9278 amu)*(0.3085) = 63.454 amu

some sources quote the lethal dose, for an average 170lbs opiate-naive individual is between 75 and 375 mg