Which element is associated with the configuration [Rn] 7s² 5f⁷?

The electron configuration [Rn] 7s² 5f⁷ corresponds to the element with atomic number 103, which is Lawrencium (Lr). However, the context of the question and the fact that the configuration indicates 5f electrons typically aligns with the actinide series. In this configuration, the [Rn] represents the electron configuration of radon, which precedes the filling of the 7s and 5f orbitals.

Given that the configuration ends in 5f⁷, it specifies an element that has seven f-electrons in its 5f subshell. Among the actinides, which include elements such as Plutonium, Americium, Curium, and Californium, Americium stands out as it is known specifically for having this configuration.

Americium (Am) has an atomic number of 95, therefore the configuration of [Rn] 7s² 5f⁷ implies that it has two 7s electrons and seven 5f electrons. This makes Americium the correct association for the provided electron configuration. The remaining elements either do not fit this configuration based on their number of f-electrons and atomic placement in the periodic