Which of the following corresponds to the electron configuration [Rn] 7s² 5f¹⁰?

The electron configuration [Rn] 7s² 5f¹⁰ indicates that we are dealing with an element that has a total of 102 electrons when you account for the noble gas core at Radon (Rn) and the additional electrons specified in the configuration.

The notation [Rn] refers to the electron configuration up to Radon, which has 86 electrons. The terms 7s² and 5f¹⁰ add a total of 12 more electrons (2 from 7s² and 10 from 5f¹⁰), bringing the total to 98 after Radon. However, continued filling of the f-orbital indicates we are in the actinide or transactinide series.

The filling of the 5f subshell leads us to elements that are part of the actinides, where the 5f orbital is progressively filled. The configuration ends with 5f¹⁰, which corresponds to Einsteinium (Es), Fermium (Fm), and Mendelevium (Md), but in this case, we focus specifically on the number of f-orbital electrons.

Californium, which has the electron configuration [Rn] 7s²