Answer:
- Rest of rare earth elements: 4f (they are part of the f-block)
- Actinide series: 5f
Explanation:
The electron subshell being filled is defined by the differential electron, which is the last electron placed in the electron configuration.
The rare earth series involves 17 elements: scandium, yttrium and 15 lanthanides. The subshell filled for these elements are:
- Rest of rare earth elements: 4f (they are part of the f-block)
The actinide series includes 15 elements. The electron subshell filled for these elements is 5f (they are part of the f-block).
