Metallic Bonds and Properties of Metals

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

Brass though a magnifier

Brass at the atomic level

Zn Cu