International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

Which of the following properties is most associated with metals?

1. Poor conductivity of heat

2. High melting and boiling points

3. Low density

4. Brittleness

The correct answer is: High melting and boiling points

The chosen property, high melting and boiling points, is fundamentally associated with metals due to their atomic structure and bonding characteristics. Metals have a crystalline structure characterized by a strong metallic bond, which results from the attraction between positively charged metal ions and delocalized electrons. This bonding gives rise to a significant amount of energy required to break the bonds during melting and boiling processes, leading to high melting and boiling points for most metals. In comparison, the other properties listed do not align with the general characteristics of metals. Poor conductivity of heat is typically seen in nonmetals, which usually do not allow heat to transfer efficiently. Low density is often characteristic of lighter materials, including many nonmetals or specific metalloids, rather than the denser substances generally observed in metals. Lastly, brittleness is more commonly associated with nonmetals and certain alloys, as most metals are malleable and ductile, allowing them to be shaped without breaking. Therefore, high melting and boiling points stand out as a hallmark feature of metals, underscoring their distinctive properties in the context of materials science.