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Physical Properties of Metals, Non-Metals, and Metalloids
Physical Properties • Definition: Properties that can be observed without making any chemical changes to the substance. • Determined by the atomic structure of the substance and the strength of the bonds.
Examples that could be easily observed in your classrooms: – Color – not always diagnostic, but sometimes can be – Luster – how the light reflects off the surface of a substance. – Malleability – the ability of a substance to be deformed under compressive stress. – Density – mass/unit volume. – Conductivity – the ability of the substance to transmit electricity or heat.
Luster Metallic Non-Metallic
Metals vs. Non-metals Metals Non-metals Color Gold, silver, copper, pyrite, some others show characteristic colors; always opaque Wide variety of colors or colorless; sometimes transparent or translucent Luster Metallic luster: think coins and jewelry; shiny or rusty Non-metallic luster: can be shiny, but looks like glass, not metal. Often dull. Malleability Can be hammered or rolled into various shapes Will shatter if hammered Density Usually heavy for its size: think lead and gold Average or light density – rarely heavy Conductivity Will conduct cold or heat; will conduct electricity when solid Will not conduct cold, heat, or electricity well.
Metalloids • B, Si, Ge, As, Sb, Te, Po (a diagonal between the metals and the non-metals on the Periodic Table of the Elements) • Can have properties of metals or non-metals, depending upon allotrope, temperature conditions, presence of an electric field, or other conditions. • Often used as semi-conductors in electrical applications. • Cannot be easily identified by your students.
For More Information, IRC: Physical Properties of Metals, Non-metals, and Metalloids