Metallic Bonding Metals in the periodic table Metals
Metallic Bonding
Metals in the periodic table
Metals Essential for Life Oops!
Properties of Metals • • • Solids (except Hg) – most have high mp & bp Luster Malleable & ductile Good conductor of heat & electricity Metals are losers! (metals lose electrons and form positive ions) • Low ionization energy • Low electronegativity
Metallic Bonding Metal atoms form a lattice. The valence levels of the atoms overlap. The valence electrons can roam easily from 1 atom to another throughout the metal. Metallic bonding
Delocalized Electrons • Valence electrons are free to roam throughout crystal • “Sea of Mobile Electrons” • Metallic Bond = attraction between positive metal kernels and electrons in electron sea. Electrons can be attracted to many cations, not just 1.
Comparison of Metallic & Ionic Bonding Lattice points are all positive. Electrons roam. Lattice points are positive and negative.
Properties of metals • Electrons can move so they conduct a current. • Electron sea holds the metal together when it’s deformed.
Metallic Bonds • Pretty strong. All metals but Hg are solids at room temperature. • Most have moderately high melting points & high boiling points.
Deformation of Metals
Why metals are deformable & ionic crystals aren’t:
Deformation of Metals • Applied force moves metal cations. • Cations are held together by electron sea.
Alloys • Mixture of elements that has metallic properties. • Adjust the mixture to get desired properties. • Can be substitutional or interstitial
- Slides: 16
