Humber Admissions Practice Test

The characteristic of being purely metallic is not applicable to metalloids. Metalloids are elements that have properties intermediate between metals and nonmetals. They often exhibit a mixture of both metallic and non-metallic characteristics, making them versatile in behavior.

Good conductors in some conditions refers to the semiconducting nature of metalloids, which allows them to conduct electricity under certain circumstances, such as in varying temperatures or with the addition of specific impurities. This property is essential for their use in electronics.

A shiny appearance is another common trait of metalloids; they often have a luster similar to metals, which contributes to their metallic-like features.

Dull and brittle describes another aspect of metalloids, particularly when compared to metals, which are typically malleable and ductile. Many metalloids, such as silicon and arsenic, can break or shatter rather than deform when subjected to stress.

Thus, the choice indicating purely metallic properties does not align with the nature of metalloids, confirming it as the correct answer to the question.