WAEC Chemistry 2025 Paper

Concept:A metalloid is an element whose properties are intermediate between those of metals and non-metals.Explanation:Aluminium ($\mathrm{Al}$) and sodium ($\mathrm{Na}$) are typical metals, while phosphorus ($\mathrm{P}$) behaves as a non-metal.Selenium ($\mathrm{Se}$) is often classified as a metalloid because it shows both metallic and non-metallic characteristics under different conditions.Hence, among the given choices, selenium is the element that best fits the definition of a metalloid.Answer:B. Selenium