8. Rare Earth Elements add their electrons to which shell? a) Last shell B) Rnd to last shell c) 3rd to last shell

To determine which shell the electrons of Rare Earth Elements (REEs) are added to, we need to understand their electronic configuration. Rare Earth Elements are primarily found in the f-block of the periodic table, specifically in the lanthanide and actinide series. The lanthanides (elements 57-71) fill the 4f subshell, while the actinides (elements 89-103) fill the 5f subshell. 1. **Last shell**: This would refer to the outermost shell, which is not where the f-electrons are added. 2. **Second to last shell**: This would refer to the shell before the outermost shell, which is where the f-electrons are added. 3. **Third to last shell**: This would refer to the shell before the second to last shell, which is not relevant for REEs. Given this information, the correct answer is: **B) Second to last shell** (the f subshell).