<u>Answer:</u> The average atomic mass of element Tyserium is 334.9 amu.
<u>Explanation:</u>
Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.
Formula used to calculate average atomic mass follows:
.....(1)
Mass of isotope 1 = 331 amu
Percentage abundance of isotope 1 = 35.0 %
Fractional abundance of isotope 1 = 0.35
Mass of isotope 2 = 337 amu
Percentage abundance of isotope 2 = 65.0 %
Fractional abundance of isotope 2 = 0.65
Putting values in equation 1, we get:
Hence, the average atomic mass of element Tyserium is 334.9 amu.