In which of the following pairs of elements are both members of the pair in the same period in the periodic table?
A) Ne and Mg
B) Ni and Pd
C) Ca and Se
D) K and Rb

Question

Quizplus · Accepted Answer

Ca and Se are both in the fourth period (row) of the periodic table. Ne is in the second period, Mg is in the third period, Ni and Pd are in the fourth period, and K and Rb are in the fourth period as well, but Ca and Se are the only pair in which both elements are in the same period.

In Which of the Following Pairs of Elements Are Both