Metallic bonds

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

Metallic Bond The electrostatic attraction of the delocalized electrons for the positively charged metal ions Electron Sea Model Made up of closely packed cations surrounded by electrons Outer e clouds of the metal ions overlap Share their electrons to form a sea of electrons What are delocalized electrons? What do we call a positive ion?

Properties of Metals 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 High melting and boiling points (also called low volatility) because of strong electrostatic force Think back to why dissolved or melted ionic compounds could conduct electrical current, why do you think metals make good conductors? Why are they malleable and ductile?

Alloys Mixture of two or more elements (at least one must be a metal) Has metallic properties often superior to those of their component elements -Bronze: copper + tin -Steel: iron + carbon + other metals -Sterling silver: silver + copper What is an alloy? Why are their properties superior?

Cu Zn Brass at the atomic level Brass though a magnifier What kind of a mixture is this? Brass at the atomic level Brass though a magnifier

Types of Alloys Substitutional Interstitial Atoms have relatively the same size Atoms of different sizes What is an alloy? Why are their properties superior?