code: def _add_atomic_percents_(elemental_array):
      
      n_atoms = _calculate_n_atoms_(elemental_array)
      for e in elemental_array:
          e["atomic_percent"] = e["occurances"] / n_atoms * 100
      return elemental_array
docs: Adds ideal atomic percents to a emperical compositional element array generated using _create_emprical_compositional_array_()
  
      :param elemental_array: an array of dictionaries containing information about the elements in the system
      :return: the elemental_array with the atomic percent of each element added