Which statement best defines a representative element in the periodic table?

• A. Any element with atomic number greater than $57$ (lanthanides and beyond)
• B. An element in the s- and p-blocks (groups 1, 2, and 13–18), excluding the transition metals
• C. An element in the f-block that fills $f$ orbitals (lanthanides and actinides)
• D. An element in the d-block (groups 3–12) that commonly forms colored ions

Answer: (B)

Verified step by step guidance

1. Understand that the periodic table is divided into blocks based on the electron configuration of the elements: s-block, p-block, d-block, and f-block.
2. Recognize that representative elements are those that have their outermost electrons in the s- and p-blocks of the periodic table.
3. Note that the s-block includes groups 1 and 2, while the p-block includes groups 13 through 18.
4. Exclude transition metals (d-block elements, groups 3–12) and inner transition metals (f-block elements, lanthanides and actinides) from the definition of representative elements.
5. Conclude that representative elements are those in groups 1, 2, and 13–18, which exhibit a wide range of chemical properties and are often used to illustrate periodic trends.