code: private static boolean aromaticElement(int element) {
          switch (element) {
              case CARBON:
              case NITROGEN:
              case OXYGEN:
              case PHOSPHORUS:
              case SULPHUR:
              case ARSENIC:
              case SELENIUM:
                  return true;
          }
          return false;
      }
docs: Is the element specified by the atomic number, allowed to be aromatic by
  the daylight specification. Allowed elements are C, N, O, P, S, As, Se
  and *. This model allows all except for the unknown ('*') element.
  
  @param element atomic number of element
  @return the element can be aromatic