Final answer:
The group name for the two rows at the bottom of the periodic table are the inner transition metals, which include the lanthanides (first row) and actinides (second row).
Step-by-step explanation:
The two rows at the bottom of the periodic table are groups that contain what are known as the inner transition metals. These are split into two series: the lanthanides and the actinides. The lanthanides are found in the first row beneath the main body of the periodic table and the actinides are in the second row. These two groups are named after elements within their series: lanthanide is named after lanthanum, the first element in that series, and actinide is named after actinium, the first element in that series.