  This contribution reviews a selection of findings on atomic density functions
and discusses ways for reading chemical information from them. First an
expression for the density function for atoms in the multi-configuration
Hartree--Fock scheme is established. The spherical harmonic content of the
density function and ways to restore the spherical symmetry in a general
open-shell case are treated. The evaluation of the density function is
illustrated in a few examples. In the second part of the paper, atomic density
functions are analyzed using quantum similarity measures. The comparison of
atomic density functions is shown to be useful to obtain physical and chemical
information. Finally, concepts from information theory are introduced and
adopted for the comparison of density functions. In particular, based on the
Kullback--Leibler form, a functional is constructed that reveals the
periodicity in Mendeleev's table. Finally a quantum similarity measure is
constructed, based on the integrand of the Kullback--Leibler expression and the
periodicity is regained in a different way.
