Answer:
The average atomic mass of Y is 123.4725 g/mol
Explanation:
The average mass of an element is calculated by taking the average of the atomic masses of its stable isotopes.
The enitre atomic mass = 100 % or 1
⇒ this consists of 57.25 % atoms with mass 123.90 g/mol
57.25 % = 0.5725
⇒ this consists of 42.75 % atoms with mass 123.90 g/mol
42.75 % = 0.4275
To calculate the mass of this isotope we use the following:
0.5725 * 123.90 + 0.4275 * 122.90 = 123.4725 g/mol
