What element corresponds to the electron configuration [Rn] 7s² 5f¹⁰?

The electron configuration [Rn] 7s² 5f¹⁰ corresponds to the element with atomic number 102, which is Nobelium. This is determined by analyzing the number of electrons in the given configuration.

In this notation, [Rn] represents the electron configuration of Radon, which has 86 electrons. The additional 7s² indicates there are 2 electrons in the 7s orbital, and 5f¹⁰ indicates there are 10 electrons in the 5f orbital. Thus, adding these gives a total of 86 + 2 + 10 = 98 electrons, which corresponds to the atomic number of Californium (Cf), not Nobelium.

The confusion can arise if the counting of electrons is either misunderstood in terms of their placement within the periodic table or if the energy levels are misinterpreted. Nobelium (No), which is atomic number 102, would correctly have the configuration [Rn] 7s² 5f¹² as it would possess two more electrons than what is indicated in the configuration provided, which aligns with the placement and designation of the f-block elements, where the 5f sublevel accommodates additional electrons.

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