Which of the following elements in period 3 of the periodic table is classified as a transition metal?

• A. Al
• B. None of the elements in period 3 are transition metals.
• C. Na
• D. Si

Answer: (B)

Verified step by step guidance

1. Recall the definition of transition metals: elements that have an incomplete d subshell in either their elemental form or common oxidation states, typically found in the d-block of the periodic table.
2. Identify the position of period 3 elements in the periodic table: period 3 includes elements from atomic number 11 (Na) to 18 (Ar), which are in the s- and p-blocks, not the d-block.
3. List the elements in period 3: Na (s-block), Mg (s-block), Al (p-block), Si (p-block), P (p-block), S (p-block), Cl (p-block), and Ar (p-block). None of these are in the d-block.
4. Understand that transition metals are located in periods 4 and beyond, starting with Scandium (Sc) in period 4, which is the first transition metal.
5. Conclude that none of the elements in period 3, including Al, Na, and Si, are classified as transition metals because they do not have partially filled d orbitals.