transition element

Definitions

1. Any element in the d block of the periodic table (i.e. groups 3 to 12 inclusive).
2. The same, but excluding the group 12 elements (i.e. groups 3 to 11 inclusive).
   dated
3. Any of the group of metallic elements that have an incomplete inner (d) electron shell, having multiple valencies and forming coloured compounds and stable complex ions.
   dated

Equivalents

CEFR level