Question

which word or group of words is represented by the word \period\ in the term periodic table?
a group
b family
c energy level
d valence electrons

Explanation:

In the Periodic Table, rows are called periods. Elements in the same period have their valence electrons in the same principal energy level (shell), so the term "period" corresponds to energy level. Groups/families refer to columns, and valence electrons define group properties, not periods.

Answer:

C. Energy Level