Which set lists three elements that are strongly magnetic (ferromagnetic) at room temperature?

• A. Copper (Cu), aluminum (Al), and zinc (Zn)
• B. Gold (Au), silver (Ag), and platinum (Pt)
• C. Iron (Fe), cobalt (Co), and nickel (Ni)
• D. Carbon (C), oxygen (O), and sulfur (S)

Answer: (C)

Verified step by step guidance

1. Understand that ferromagnetism is a property of certain materials that exhibit strong, permanent magnetism at room temperature due to the alignment of magnetic moments in domains.
2. Recall that common ferromagnetic elements include Iron (Fe), Cobalt (Co), and Nickel (Ni), which have unpaired electrons in their d-orbitals allowing magnetic domains to form.
3. Recognize that elements like Copper (Cu), Aluminum (Al), Zinc (Zn), Gold (Au), Silver (Ag), Platinum (Pt), Carbon (C), Oxygen (O), and Sulfur (S) are not ferromagnetic at room temperature because their electron configurations do not support stable magnetic domain formation.
4. Identify the set that contains Iron (Fe), Cobalt (Co), and Nickel (Ni) as the correct group of strongly magnetic (ferromagnetic) elements at room temperature.
5. Conclude that the correct answer is the set with Iron, Cobalt, and Nickel, based on their well-known ferromagnetic properties.