D-block (for diffuse) elements consist of the transition metals (group 3-12 on the periodic table) in which the outermost electron shell is the D orbital. D-block elements form at least one stable ion with an incompletely filled electron subshell.
... biologist and explorer
Alexandra David-Néel, (1868-1969), French explorer, visited Lhasa, Tibet in 1924
Cavalier de la Salle[?], explorer
Hernando de Soto, (died ...