Which type of elements are lanthanides and actinides part of? halogens inner transition metals metals noble gases

Elements: Gadolinium; Lutetium; Cerium

Explanation:

The lanthanide and actinide series make up the inner transition metals. The lanthanide series includes elements 58 to 71, which fill their 4f sublevel progressively. The actinides are elements 89 to 103 and fill their 5f sublevel progressively.

a:

by the combination of an unlimited number of elements

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.