Which of the following best explains why the d block of the periodic table is wider than either the s block or the p block?

• A. The d block is wider because transition metals have higher atomic numbers than s and p block elements.
• B. The d block contains ten groups because there are five d orbitals, each holding two electrons.
• C. The d block is wider because it includes both metals and nonmetals.
• D. The d block is wider due to the presence of inner core electrons.

Answer: (B)

Verified step by step guidance

1. Recall that the periodic table is divided into blocks based on the type of atomic orbitals being filled with electrons: s, p, d, and f blocks.
2. Understand that the width of each block corresponds to the number of groups (columns) it contains, which is related to the number of orbitals available in that block.
3. Recognize that the s block has 1 orbital (s orbital) which can hold 2 electrons, so it spans 2 groups.
4. Know that the p block has 3 orbitals (p orbitals), each holding 2 electrons, so it spans 6 groups.
5. Realize that the d block has 5 orbitals (d orbitals), each holding 2 electrons, so it spans 10 groups, making it wider than the s and p blocks.