Structure and Properties of Solids

Ionic Crystals (5)

• alternating positive and negative ions

• arranged to minimize distance between opposite charges, maximize distance between like charges

• type of packing/shape depend on size and charge of ion

• solids do not conduct, aqueous solutions or molten do

• high MP, strong ionic bonds

Metallic Crystals (General Characteristics) (4)

• not all the same properties

• closely packed atoms, valence electrons delocalized around positive nucleus

• floating electrons hold positive nuclei together, creating a metallic bond due to the electrostatic attraction

• metals involved must have low ionization energy, do not hold electrons tightly

Metallic Crystals (Physical Properties) (5)

• lustre: absorb and emit NRG of all wavelengths of light

• electric conductivity: mobile valence e’s with electrical force applied

• heat conductivity: heat applied increase electrons speed, motion transferred, heating full crystal

• malleable and ductile

• hardness: strong electrostatic forces

Molecular Crystals (8)

• held in space as molecules

• certain in solid state, some variations

• solid crystal held by weak IMF

• polar held by dipole-dipole, some held by h-bonding or london forces

• nonpolar held by london

• non-conductive (nonpolar molecules)

• soft

• low MP

Covalent Network Crystal (4)

• covalent bonds in 2D and 3D network

• high MP

• hard due to interlocking network of carbons in various shapes/patterns

• poor conductors, covalent bonds hold e’s in space