On the periodic table,elements in the same period contain the same number of
A)protons.
B)electrons.
C)principal energy levels in their ground state.
D)valence electrons in their ground state.

Question

Quizplus · Accepted Answer

The number of principal energy levels in an element's ground state increases as you move down a group (or column) on the periodic table. This means that elements in the same period (or row) have the same number of principal energy levels in their ground state. Therefore, choice C is the correct answer. Choices A, B, and D are incorrect because they refer to properties of elements within a group, not a period.

On the Periodic Table,elements in the Same Period Contain the Same