Which of the following is NOT a characteristic of non-metals?

Non-metals typically exhibit specific characteristics that differentiate them from metals. Among these characteristics, being dull is a common trait; non-metals generally lack the shiny luster that metals possess. Non-metals are also often brittle when they are solid, meaning they can break easily when subjected to stress, unlike metals which tend to be malleable and ductile.

Another key feature of non-metals is that they are poor conductors of electricity and heat, making them insulators rather than conductors. Therefore, options related to dullness, brittleness, and being poor conductors align well with the common properties seen in non-metals.

However, the characteristic of being shiny is not associated with non-metals. Instead, this trait is generally linked to metals, which reflect light and have a lustrous appearance. Hence, non-metals do not exhibit shininess, making it the correct choice for the characteristic that is NOT typical of non-metals.