The "GetExplicitHCount" method returns the number of explicit
hydrogens attached to an atom, i.e. the number of neighbors with
atomic number OEElemNo.H.
The "IsConnected" method tests whether a bond exists from the
calling atom to the atom passed as an argument to the method. If a
bond between the two atoms exists, the method returns true. If no
bond exists, the method returns false.
The "IsHalogen" method tests whether the given atom is a fluorine,
chlorine, bromine, or Iodine. i.e. has one of the following atomic
numbers: (OEElemNo.F, OEElemNo.Cl,
OEElemNo.Br, OEElemNo.I).
The "IsPolarHydrogen" method tests whether the given atom is a
hydrogen, i.e. has atomic number of one (OEElemNo.H), and is
not connected to either a carbon or another hydrogen.