Which of the following elements is likely to be the most brittle?

• A. Cobalt
• B. Zinc
• C. Platinum
• D. Selenium

Answer: (D)

Verified step by step guidance

1. Understand the concept of brittleness: Brittleness is a property of materials that describes their tendency to break or shatter without significant deformation when subjected to stress.
2. Recognize that metals like cobalt, zinc, and platinum are generally ductile, meaning they can deform plastically before breaking, so they are less likely to be brittle.
3. Identify that selenium is a nonmetal or metalloid, which typically have more brittle characteristics compared to metals due to their atomic structure and bonding.
4. Compare the bonding and structure of the elements: Metals have metallic bonding allowing atoms to slide past each other, reducing brittleness, while nonmetals/metalloids like selenium have covalent or directional bonds that make them more brittle.
5. Conclude that selenium is likely the most brittle element among the options because its bonding and structure do not allow for much plastic deformation before fracture.