How many moles of magnesium is 3.51 × 10 ^24 atoms of magnesium

3.51 should be the answer idk 

Atoms are the smallest form of the substance. examples of atoms are in elemental forms such as copper, helium, silver. Diatomic molecules are made up of identical atoms. Examples are I2.. F2 and Br2. Formula units are those compounds that are made up of two or more elements such as -No2, KMnO4,C3H8, MgCl2, HgBr2, Ba(OH)2