Multiple Choice
Why is the configuration of electrons in an atom's outer shell important?
3
views
10. Periodic Properties of the Elements
Valence Electrons of Elements
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which atom in the ground state has a valence electron with the greatest amount of energy?
A
Cs
B
Na
C
K
D
Li
Verified step by step guidance1
Understand that the valence electron energy depends on the principal quantum number (n) and the effective nuclear charge experienced by the electron. Electrons in higher energy levels (larger n) generally have higher energy.
Identify the group and period of each element: Li (period 2), Na (period 3), K (period 4), and Cs (period 6). All are in group 1 (alkali metals) with one valence electron in an s orbital.
Recognize that the valence electron for each element is in the outermost s orbital: Li in 2s, Na in 3s, K in 4s, and Cs in 6s. The higher the principal quantum number, the higher the energy of the valence electron.
Consider that although effective nuclear charge increases with atomic number, the increase in principal quantum number has a stronger effect on the energy of the valence electron, making electrons in higher shells less tightly bound and higher in energy.
Conclude that Cs, with its valence electron in the 6s orbital, has the valence electron with the greatest amount of energy among the given options.
2:32mWatch next
Master Main Group Elements Valence Electrons with a bite sized video explanation from Jules
Start learningRelated Videos
Related Practice
Valence Electrons of Elements practice set
Problem sets built by lead tutorsExpert video explanations