Which of the following best describes the difference between periods and groups on the periodic table?

• A. Periods are vertical columns, while groups are horizontal rows.
• B. Periods are used to classify metals and nonmetals, while groups are used to classify metalloids.
• C. Periods contain elements with similar chemical properties, while groups contain elements with increasing atomic number.
• D. Periods are horizontal rows, while groups are vertical columns.

Answer: (D)

Verified step by step guidance

1. Understand that the periodic table is organized into two main types of arrangements: periods and groups.
2. Recognize that periods are the horizontal rows on the periodic table. Each period corresponds to elements with increasing atomic number from left to right.
3. Know that groups are the vertical columns on the periodic table. Elements in the same group share similar chemical properties because they have the same number of valence electrons.
4. Recall that the key difference is that periods show trends in properties across a row, while groups show similarities down a column.
5. Therefore, the best description is: Periods are horizontal rows, while groups are vertical columns.