Which of the following are not representative elements ?
Li, K, Al, Cu, Ne, Fe, S, Ce, Th

Explanation

To determine which of the given elements are not representative elements, we first need to understand what representative elements are. Representative elements are those found in the s and p blocks of the periodic table. The d and f block elements are not considered representative elements.

Let's analyze the given elements one by one:

1. **Lithium (Li)**:
- Electronic configuration: He 2s¹
- Block: s block
- Conclusion: Representative element
...