Question

What is the atomic mass of the given element ‘X’?

Answer 1

Answer:

The average relative atomic mass of element X is 220.4.

Step-by-step explanation:

75

%

of all X atoms are X-28, which means that

25

%

of all X atoms are X-24 as there are only 2 isotopes.

Then, you do the mass number multiplied by its percentage, and add those two together and you'll get the atomic mass of that element. If there are more isotopes, just use the same method for all of the isotopes.