Nokea
On the periodic table, families of elements with similar properties appear in the same _________.
Correct Answer: D
Rationale: Families of elements with similar properties appear in the same column on the periodic table. Columns are also known as groups, and elements within the same group have similar chemical and physical properties due to their identical number of valence electrons. Therefore, the correct answer is 'column.'
Choice A, 'row,' is incorrect because rows on the periodic table are called periods, not families or groups of elements.
Choice B, 'principal energy level,' is incorrect as it refers to the energy levels of electrons around the nucleus of an atom, not the arrangement of elements with similar properties on the periodic table.
Choice C, 'period,' is incorrect as periods represent horizontal rows on the periodic table, where elements do not necessarily have similar properties compared to elements in the same column.