Solids

Metallic Crystals Alloys – mixtures of metals – done to

strengthen or make a metal less brittle or subject to oxidation.

2 types Substitutional – when metal atoms

are of similar size Interstitial – when one atom is

smaller than the other, fills in the spaces between the larger ones

Substitutional Interstitial

Solids

Metallic crystals Substitutional alloy

Silver alloyed with gold, replace one set of attractive forces with an almost equal set of attractive forces with the added metal. Result: alloy has properties that

tend to fall somewhere between the two separate metals

Solids

Metallic crystals Interstitial alloys

Incorporate one atom into the existing structure with little change in volume- results in increased density

Increases total attractive forces in the alloy

Usually stronger and harder than original materials

Solids

Ionic Crystals Attraction of a cation and an anion is

the strongest attractive force known in chemistry. Alternating positive & negative

ions Almost all ionic compounds are

solids with rigid crystal structures (lattices)

Take a large amount of lattice energy to separate the ions!