virtual unsigned int GetAtomicNum() const
Return the atomic number of the atom. A value of zero is returned for
wildcard atoms, such as MDL super atoms. An atomic number is specified
as the argument to OEAtomBase::NewAtom
and may be changed using
OEAtomBase::SetAtomicNum
. The set of unsigned integer values for
this property are defined by the OEElemNo
namespace.