Question

Determine whether the following electron configurations are or are not valid.

1.[Rn] 7s^2 5f^9
2. [Xe]
3. [Ne] 3p^5 3s^2

Answer 1

The first electron configuration is not valid because it exceeds the maximum number of electrons in the 5f sublevel. The second electron configuration is valid and represents a noble gas. The third electron configuration is valid and represents a sulfur atom.

Step-by-step explanation:

The electron configurations are as follows:

Among the provided electron configurations, the first (representing element Berkelium) and the second (representing noble gas Xenon) are valid. The third configuration is not valid because it incorrectly orders the subshells and improperly fills them.

The question asks about the validity of certain electron configurations and relates to the understanding of electronic structures of atoms in chemistry. The configurations provided are:

1. [Rn] 7s2 5f9
2. [Xe]
3. [Ne] 3p5 3s2

To check these configurations:

The first configuration represents the element after Radon (Rn) with two electrons in the 7s subshell and nine in the 5f subshell. The atomic number for Rn is 86, so this configuration represents the element with atomic number 97, which is Berkelium (Bk), and it is a valid configuration.

The second configuration represents the noble gas Xenon (Xe), which is complete and, therefore, a valid electron configuration.

The third configuration is not valid because it lists the 3p subshell before the 3s subshell and more electrons are assigned to the 3p subshell than to the 3s. In a correct configuration, electrons fill the 3s subshell before the 3p subshell, and the 3s subshell must be filled with two electrons before electrons can be added to the 3p subshell.