What is the number of magnesium atoms that equal a mass of 24.31 amu?

Atomic Mass of Magnesium = 24.30 amu

As we know, 1 mole of Mg weights exactly 24.30 amu.

Also,

1 mole of Mg contains 6.022 * 10²³ Atoms.

So, If,

24.30 amu Mg contains = 6.022 * 10²³ Mg Atoms

Then,

24.31 amu of Mg will contain = X Mg Atoms,

Solving for X,

X = (24.31 amu * 6.022 * 10²³ Atoms) : 24.30

X = 6.022 * 10²³ Mg Atoms

Result:

24.31 amu of Mg equals 6.022 * 10²³ Mg Atoms.