Find the number of atoms in 237g cu (molar mass of cu63.55g/mol)

In order to find the amount of atoms you have to find the moles then multiply by Avogadro's Constant (L)

mol = 
 
       = 
       
       =  3.73 mol

Number of atoms of Cu =  mol × L
                
                                      = 3.73 mol × (6.02 × 10²³)
                          
                                      = 2.245 × 10²⁴ atoms of copper