Chapter 5.4 Bonding in Metals

Standards: 8.7.c. Students know substances can be classified by their properties, including their melting temperature, density, hardness, and thermal and electrical conductivity.

Metals and Alloys Alloy: A mixture of two or more elements, at least one of which is a metal Alloys are generally stronger and less reactive than the pure metals from which they are made.

Physical & Chemical Properties Alloys retain many of they typical physical properties of metals Pure iron will rust faster, and silver will tarnish, whereas stainless steel can be washed over and over again and resist rust and tarnishing.

Metallic Bonding Metal atoms combine in regular patterns in which the valence electrons are free to move from atom to atom. Metallic Bond: an attraction between a positive metal ion and many electrons surrounding it.

Metallic Properties The “sea of electrons” model of metallic bonding helps explain the malleability, ductility, luster, high electrical conductivity, and high thermal activity of solid metals

Malleablility & Ductility Malleable: able to form into thin sheets Ductility: able to be drawn into wires

More Vocab Words Luster: Shiny and reflective Electrical conductivity: electricity can easily flow through it Thermal conductivity: heat can easily flow through it