Which of the following is a property commonly associated with metalloids?

• A. They are always malleable and ductile.
• B. They are excellent conductors of heat and electricity.
• C. They react vigorously with water.
• D. They have intermediate electrical conductivity.

Answer: (D)

Verified step by step guidance

1. Understand that metalloids are elements with properties intermediate between metals and nonmetals.
2. Recall that metals are typically malleable and ductile, while nonmetals are not; metalloids may have some but not all metallic physical properties.
3. Recognize that excellent conductors of heat and electricity are usually metals, whereas metalloids have electrical conductivity that is between metals and nonmetals.
4. Note that vigorous reaction with water is characteristic of some highly reactive metals, not metalloids.
5. Conclude that the key property of metalloids is their intermediate electrical conductivity, which makes them useful as semiconductors.