code: private IAtom getNextAtomWithAliphaticUnplacedNeigbors() {
          IBond bond;
          for (int f = 0; f < molecule.getBondCount(); f++) {
              bond = molecule.getBond(f);
  
              if (bond.getEnd().getFlag(CDKConstants.ISPLACED) && !bond.getBegin().getFlag(CDKConstants.ISPLACED)) {
                  return bond.getEnd();
              }
  
              if (bond.getBegin().getFlag(CDKConstants.ISPLACED) && !bond.getEnd().getFlag(CDKConstants.ISPLACED)) {
                  return bond.getBegin();
              }
          }
          return null;
      }
docs: Returns the next atom with unplaced aliphatic neighbors
  
  @return the next atom with unplaced aliphatic neighbors