code: private void addAtom(String newAtomType, IAtom otherConnectingAtom, Order bondOrder, int hydrogenCount) {
          //Create the new atom and bond.
          IAtom newAtom = currentMolecule.getBuilder().newInstance(IAtom.class, newAtomType);
          newAtom.setImplicitHydrogenCount(hydrogenCount);
          IBond newBond = currentMolecule.getBuilder().newInstance(IBond.class, newAtom, otherConnectingAtom, bondOrder);
  
          //Add the new atom and bond to the molecule.
          currentMolecule.addAtom(newAtom);
          currentMolecule.addBond(newBond);
      }
docs: Adds an atom to the current molecule.
  
  @param newAtomType The atomic symbol for the atom.
  @param otherConnectingAtom An atom already in the molecule which
  the new one should connect to.
  @param bondOrder The order of the bond to use to join the two atoms.
  @param hydrogenCount The number of hydrogen atoms connected to this atom.