Metals

Metallic Solids

Crystaline solids consisting of metal cations arranged in a regular lattice, surrounded by a sea of delocalized valance electrons.

________ are model led as hard spheres

Delocalized electrons

are electrons in a molecule, ion or solid metal that are not associated with a single atom or a covalent bond.

Instead, they spread out over three or more adjacent atoms.

Strong cohesive force

The valence electrons are delocalized throughout the crystal... Providing a _________

Closed Packing

Metals ____ efficiently to maximize attractive forces and minimize empty space

Metallic Solids

Ionic Solids

Covalent-network solids

Molecular solids

Types of Solids according to Bonding

Properties of Metallic Solids

Good conductors of heat and electricity

Melting points depend strongly on electron configuration

Easily deformed under stress ductile and malleable.

Usually high density

Lustrous

Electron Sea Model

Band Theory

Models of Metallic Bonding

Electron Sea Model

Metal cations are surrounded by a sea of mobile, delocalized valence electrons.

Band Theory

Atomic orbitals overlap to form continuous energy bands

Valence band: filled with electrons

Conduction band: Empty or partially filled, allows electron movement explains difference between conductors, semiconductors and insulators

Good Electrical Conductors

Metals are __________ because their delocalized electrons carry electrical charge through the metal

Good Thermal Conductor

________ Because their delocalized electrons transfer energy

High melting and boiling points

________ because the metallic bonding is the giant structure of a metal is very strong... Large amounts of energy are needed to overcome the metallic bonds in melting and boiling

Malleability

Ability of the substance to be bent and hammered into thin sheets without breaking

Ductility

Ability of the substance to be streatched into a wire

Shiny

Delocalized electrons absorb and immediately re emit photons of visible light

Alloys

Homogeneous mixture of two or more elements where at least one is a metal

For enhancement of properties such as hardness, strength, corrosion resistance, melting point and appearance. Pure iron is soft, but steel is strong

Substitutional Alloy

Atoms of similar sizes swap places in the crystal lattice

Atomic sizes must be similar

Brass equals Copper plus Zinc

Sterling Silver Silver plus Copper

White Gold Gold plus Nickel

Interstitial Alloy

Smaller atoms fit into the spaces between larger metal atoms

Carbon Steel Iron plus Carbon

Stainless Steel Iron plus Chromium plus Nickel plus Carbon

Substitional Alloy

Interstitial Alloy

Two types of Alloys