Question

If a sample contains equal amounts of two stable isotopes of an element, how would the average atomic mass of the element be affected compared to its individual isotopic masses?
1 point
The average atomic mass will be equal to the mass of one of the isotopes.
The average atomic mass will be the weighted average of the two isotopic masses.
The average atomic mass will be lower than the mass of the lighter isotope.
The average atomic mass will be higher than the mass of the heavier isotope.

Answer 1

The correct answer is: **The average atomic mass will be the weighted average of the two isotopic masses.**

When a sample contains equal amounts of two stable isotopes, the average atomic mass is calculated as the weighted average of the isotopic masses, taking into account their relative abundances. Since both isotopes are present in equal amounts, the average atomic mass will be the arithmetic mean of the two isotopes' masses.