How many Mg atoms are presented in 3.00 moles of MgCl2

1.81 x 10²⁴ atoms

Explanation:

To find the number of atoms in the given number of moles, we need to understand that every substance contains the Avogadro's number of particles.

More appropriately, a mole of any substance will contain the Avogadro's number of particles which is 6.02 x 10²³ atoms

 So;

           If 1 mole of a substance  = 6.02 x 10²³ atoms;

               3 mole of MgCl₂ will contain 3 x 6.02 x 10²³ = 1.81 x 10²⁴ atoms