Which element is represented by the electron configuration [Rn] 7s² 5f¹⁴?

The electron configuration [Rn] 7s² 5f¹⁴ indicates that the element in question is one that has a filled 5f subshell, characteristic of elements in the actinide series starting from actinium (Ac) through to lawrencium (Lr). The presence of 5f¹⁴ shows that all the f orbitals in the fifth energy level are fully occupied. Additionally, the presence of 7s² indicates that there are two electrons in the 7s orbital.

This configuration directly corresponds to Nobelium (No), which is atomic number 102, placing it after fermium (atomic number 100) and mendelevium (atomic number 101) in the actinide series. Nobelium is known for having this specific electron configuration, making it distinctly identifiable. The completion of these subshells and the arrangement according to increasing atomic number provide a clear rationale for Nobelium being the correct answer.