code: public IAtom getNextUnplacedHeavyAtomWithAliphaticPlacedNeighbour(IAtomContainer molecule) {
          Iterator<IBond> bonds = molecule.bonds().iterator();
          while (bonds.hasNext()) {
              IBond bond = bonds.next();
              if (bond.getBegin().getFlag(CDKConstants.ISPLACED) && !(bond.getEnd().getFlag(CDKConstants.ISPLACED))) {
                  if (isAliphaticHeavyAtom(bond.getEnd())) {
                      return bond.getEnd();
                  }
              }
              if (bond.getEnd().getFlag(CDKConstants.ISPLACED) && !(bond.getBegin().getFlag(CDKConstants.ISPLACED))) {
                  if (isAliphaticHeavyAtom(bond.getBegin())) {
                      return bond.getBegin();
                  }
              }
          }
          return null;
      }
docs: Gets the nextUnplacedHeavyAtomWithAliphaticPlacedNeighbour from an atom container or molecule.
  
  @param molecule
  @return    The nextUnplacedHeavyAtomWithAliphaticPlacedNeighbour value
  author:    steinbeck,cho