How many groups are present on the modern periodic table?

• A. 12
• B. 18
• C. 20
• D. 7

Answer: (B)

Verified step by step guidance

1. Understand that the modern periodic table is organized into vertical columns called groups, which represent elements with similar chemical properties.
2. Recall that the groups are numbered from 1 to 18, starting from the leftmost column (alkali metals) to the rightmost column (noble gases).
3. Recognize that these 18 groups include both the main-group elements and the transition metals, as well as the noble gases.
4. Note that the number 7 corresponds to the number of periods (horizontal rows), not groups, and 12 and 20 are incorrect counts for groups.
5. Therefore, the total number of groups in the modern periodic table is 18.