What is early transition metal?

Early transition metals are does starting at the beginning of the transition metals (i.e. Sc) and going through about d5 which would be Mn. These metals are less electron rich as compared to the so-called "late" transition metals and the chemistry of each is somewhat different and definitely unique. Hardness and softness of the each of these groups changes (see Hard Soft Acid Base Theory) as does the stable oxidation states and coordination numbers.