Question

which of the following is true about the electron configurations of the representative elements?
the highest occupied s and p sublevels are completely filled.
the electrons with the highest energy are in a d sublevel.
the highest occupied s and p sublevels are partially filled.
the electrons with the highest energy are in an f sublevel.

Explanation:

Representative elements (main - group elements) have their highest - energy electrons in \(s\) and \(p\) sublevels. The electron configuration of representative elements is such that the highest - occupied \(s\) and \(p\) sublevels are partially filled. Noble gases (a subset of representative elements in a sense, as they are in Group 18) have completely filled \(s\) and \(p\) sublevels, but other representative elements (e.g., Group 1 has \(ns^{1}\), Group 2 has \(ns^{2}\), Group 13 has \(ns^{2}np^{1}\) etc.) have partially filled \(s\) and \(p\) sublevels. Transition elements have electrons in \(d\) sublevels as their highest - energy electrons in some cases, and inner - transition elements have electrons in \(f\) sublevels.

Answer:

The highest occupied \(s\) and \(p\) sublevels are partially filled.