Which statement correctly describes both the 3s and 3p energy levels in the lowest-energy electron configuration of the phosphide anion P³⁻ ?

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11ecba2d_11f6_e321_a3bf_792680b90247_MD0008_00 An electron configuration accounts for the placement of all electrons within the shells and subshells of an atom or ion. Shells are indicated using the principal quantum number n, which relates to the distance of an orbital from the nucleus. Subshells are labeled by type (s, p, d, or f), which relates to the shapes of the occupied orbital, which hold a maximum of 2, 6, 10, and 14 electrons, respectively. Electron configurations are listed sequentially in order of increasing energy. Elemental atoms contain an equal number of protons and electrons, resulting in no net charge. If an elemental atom gains or loses electrons and an ion is formed, the charge of the ion is determined by how many electrons are gained or lost. If electrons are lost (cation formation), electrons in the highest-energy filled shell/subshell level are removed first. Likewise, if electrons are gained (anion formation), the lowest-energy unfilled shell/subshell level is filled first. An elemental atom of phosphorus has a total of 15 electrons and 15 protons (no net charge) with an electron configuration of 1s²2s²2p⁶3s²3p³. Therefore, a phosphide anion is the result of an elemental phosphorus atom gaining 3 additional electrons within the half-filled 3p subshell. As a result, the phosphide anion has a total of 18 electrons with a configuration of 1s²2s²2p⁶3s²3p⁶. This gives the phosphide anion a −3 charge and filled 3s and 3p energy levels. (Choices A and C) Lower energy shells/subshells must be fully filled before electrons can be added to higher energy shells/subshells. The 3s level must be filled before adding electrons to 3p. (Choice B) This is the lowest-energy electron configuration of a phosphorus atom rather than a phosphide anion. Educational objective: An electron configuration accounts for all electrons held by an atom or ion, listed sequentially by shell and subshell in order of increasing energy. During cation formation, electrons are lost from the highest-energy filled shell/subshell first; during anion formation, electrons are added to the lowest-energy unfilled shell/subshell first.

Which Statement Correctly Describes Both the 3s and 3p Energy