Which element is represented by the electron configuration [Xe] 6s² 4f⁶?

The electron configuration provided, [Xe] 6s² 4f⁶, indicates that the element in question has a total of 6 electrons in the 4f subshell. The sequence of filling the f-orbitals begins with Lanthanides, where the 4f subshell progressively fills with electrons.

When determining which element corresponds to the configuration, we need to focus on the specific number of electrons in the 4f subshell. Here, with 6 electrons in the 4f subshell, we identify that the electrons fill according to the following order in the f-block:

• 4f¹: Lanthanum (La)

• 4f²: Cerium (Ce)

• 4f³: Praseodymium (Pr)

• 4f⁴: Neodymium (Nd)

• 4f⁵: Promethium (Pm)

• 4f⁶: Samarium (Sm)

Thus, Samarium is the element that has the 4f subshell filled to the sixth position. The period for samarium is appropriate, as following the xenon core ([Xe]), we see the correct filling of the 6s orbital complements the