Metallic Bonds and Properties of Metals. Metals Metals are made up of closely packed cations...
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Transcript of Metallic Bonds and Properties of Metals. Metals Metals are made up of closely packed cations...
Metals
• Metals are made up of closely packed cations surrounded by electrons, rather than neutral atoms or ions
• Outer electron clouds of the metal ions overlap
• Electron sea model – metals in a solid contribute their valence electrons to form a “sea of electrons”– Valence electrons are not held by any specific atom and
can move easily from one atom to the next
• Delocalized electrons –are free to move in the “sea of electrons”
Metallic Bond• Definition: The attraction of the delocalized
electrons for the positively charged metal ions• Metal bonded to metal• Each ion is bonded to all neighboring cations
by the “sea” of valence electrons
Properties of Metals
• In general, metals have moderately high melting and boiling points
• Good conductors of heat and electricity
• Malleable and Ductile– Mobile electrons can easily be pushed or pulled
past each other
Structure of Metals
• Metal atoms are arranged in very compact and orderly patterns
• Metals that contain just one kind of atom are among the simplest forms of all crystalline solids
Metal Alloys
• Alloy is a mixture of two or more elements (at least one must be a metal)
• Alloy has metallic properties often superior to those of their component elements-Bronze: copper + tin-Steel: iron + carbon + other metals-Sterling silver: silver + copper