code: private boolean familyHalogen(IAtom atom) {
          String symbol = atom.getSymbol();
          return symbol.equals("F") || symbol.equals("Cl") || symbol.equals("Br") || symbol.equals("I");
      }
docs: Looking if the Atom belongs to the halogen family.
  
  @param  atom  The IAtom
  @return       True, if it belongs