Question

the valence electrons of group 4a elements are in the 5s subshell. period 5 elements all have six 5p electrons. the highest principal enegy level of period 4 elements is 4. the valence electrons of group 3a elements are in an s and p subshell. group 8a elements in the p block have full outer principal s and p subshells. the highest principal energy level of period 4 elements is 5. period 5 elements have an inner electron configuration of kr. period 3 elements have an inner electron configuration of ar.

Explanation:

Step1: Analyze each statement

• "The valence electrons of group 4A elements are in the 5s subshell."

Group 4A elements (e.g., C, Si, Ge, Sn, Pb) have valence - electron configurations of \(ns^{2}np^{2}\). For example, carbon (\(C\)) has a valence - electron configuration of \(2s^{2}2p^{2}\), silicon (\(Si\)) has \(3s^{2}3p^{2}\). So this statement is False.

• "Period 5 elements all have six 5p electrons."

Period 5 elements fill the \(5s\), \(4d\), and \(5p\) orbitals. For example, rubidium (\(Rb\)) has an electron configuration of \([Kr]5s^{1}\), strontium (\(Sr\)) has \([Kr]5s^{2}\), yttrium (\(Y\)) has \([Kr]4d^{1}5s^{2}\). Only group 8A (noble gases) in period 5 (xenon, \(Xe\): \([Kr]4d^{10}5s^{2}5p^{6}\)) has six 5p electrons. So this statement is False.

• "The highest principal energy level of period 4 elements is 4."

The period number in the periodic table is equal to the highest principal energy level (\(n\)) of the elements in that period. So this statement is True.

• "The valence electrons of group 3A elements are in an s and p subshell."

Group 3A elements have valence - electron configurations of \(ns^{2}np^{1}\). For example, boron (\(B\)) has \(2s^{2}2p^{1}\), aluminum (\(Al\)) has \(3s^{2}3p^{1}\). So this statement is True.

• "Group 8A elements in the p - block have full outer principal s and p subshells."

Group 8A (noble gases) have electron configurations of \(ns^{2}np^{6}\) (except helium which has \(1s^{2}\)). So they have full outer \(s\) and \(p\) subshells. This statement is True.

• "The highest principal energy level of period 4 elements is 5."

As mentioned before, the period number is equal to the highest principal energy level. Period 4 elements have \(n = 4\) as the highest principal energy level. So this statement is False.

• "Period 5 elements have an inner electron configuration of [Kr]."

The electron configuration of \(Kr\) is \([Ar]3d^{10}4s^{2}4p^{6}\). Period 5 elements start filling from the \(5s\) orbital. The inner - electron configuration (core electrons) of period 5 elements is \([Kr]\). For example, rubidium (\(Rb\)): \([Kr]5s^{1}\), strontium (\(Sr\)): \([Kr]5s^{2}\). This statement is True.

• "Period 3 elements have an inner electron configuration of [Ar]."

The electron configuration of \(Ar\) is \([Ne]3s^{2}3p^{6}\). Period 3 elements (e.g., sodium (\(Na\)): \([Ne]3s^{1}\), magnesium (\(Mg\)): \([Ne]3s^{2}\)) have an inner - electron configuration of \([Ne]\), not \([Ar]\). So this statement is False.

Answer:

True:

• The highest principal energy level of period 4 elements is 4.
• The valence electrons of group 3A elements are in an s and p subshell.
• Group 8A elements in the p - block have full outer principal s and p subshells.
• Period 5 elements have an inner electron configuration of [Kr].

False:

• The valence electrons of group 4A elements are in the 5s subshell.
• Period 5 elements all have six 5p electrons.
• The highest principal energy level of period 4 elements is 5.
• Period 3 elements have an inner electron configuration of [Ar].