code: @Override
      public void setAtom(IAtom atom, int position) {
          if (atoms[position] == null && atom != null) atomCount++;
          if (atoms[position] != null && atom == null) atomCount--;
          atoms[position] = atom;
      }
docs: Sets an Atom in this bond.
  
  @param atom     The atom to be set
  @param position The position in this bond where the atom is to be inserted
  @see #getAtom