CHAPTER 16 SOLIDS

All crystals of the same substance have the same angles between
	Faces (Steno's law)
Extensive properties (amount of matter present-ex mass, length,
volume) of crystals of the same substance may vary
Intensive properties (do not depend on matter present-ex
density, malleability, ductility, conductivity) remains the same

16-1 crystals
A study of the solid state is a study of crystals
A crystal is a rigid body in which the particles are arranged 
	A repeating pattern

16-2 unit cells
The unit cell is the simplest repeating unit in a crystal
The repetition of the unit cell in a crystal forms an imaginary
	Lattice of particles called a space lattice

16-3 compound unit cells
Elements from group 1 combine with elements from group 17 to
form simple salts with the face centered cubic lattice structure

16-4 Closest Packing
Cubic closest packing and face-centered cubic are the same
	Arrangement
Pure metallic elements generally form crystals in a type of 
	Closest-packing arrangement

16-5 elementary crystals
Molecular substances form crystals in which the molecules are
held together by weak Van Der Waal forces and have low melting points

16-6 network crystals
A macromolecule, or network crystal, consists of a single molecule
with all component atoms bonded in a network fashion/ have high
melting points

16-7 Isomorphism and Polymorphism
Crystals of different solids with the same structure and shape are
isomorphous
A polymorphous substance has 2 or more crystalline shapes

16-8 crystal defects
Crystal defects are imperfections in the regular repetition of
	The unit cell arrangement.  Defects can be a result of
	Displaced or missing particles. Other defects are edge
	Dislocations and screw dislocations

16-9 semiconductors
When a crystal is doped, impurities are added deliberately
Doping is important in the production of transistors
	Creates spots with extra e- or holes where e- may go

16-10 hydrated crystals
Hydrated ions are chemically bonded to water molecules
Anhydrous means without water
Hygroscopic substances attract water molecules from the air
Deliquescent substances take up enough water from the air to form
	A liquid solution

16-11 Liquid crystals
A crystalline solid is highly ordered
A liquid is disordered in all three dimensions
Solids that lose their crystalline order in only 1 or 2
 	dimensions at the melting point form liquid crystals
Smectic substances retain 2 dimensional order
Nematic substances retain order in only one dimension

16-12 amorphous material
An amorphous material appears solid but has a disordered 
	Arrangement of its particles
Crystals possess long-range order, while liquids possess short
	Range order
Crystals are said to undergo cleavage when they break, glasses
	Are said to fracture
Viscosity is the resistance of a liquid to flow
	Viscosity decreases as temperature increases