metallic bonding principles
valence e- are donated to electron sea, nuclei are attracted to the e-sea
- bonds are not rigid
ionic bonding principles
cations and anions are held tgt, the electric charges hold the structure tgt and the atoms have large differences in electronegativity
- rigid bonds
covalent (molecular) bonding principles
atoms share e- thru hybrid orbitals, they hv little-no diff in electronegativity
- rigid bonds
covalent network bonding principles
continuous 3d network, share e- thru hybrid orbitals and hv little-no difference in electronegativity
- rigid bonds
ionic bulk physical properties
- highly symmetric crystals
- brittle, not ductile
- hardness depends on ionic charge difference
- bad conductivity as a solid, good as liquid/dissolved
- solubility: ionic charge diff/radius
covalent (molecular) bulk physical properties
- depends on polarity
- strong bonds=large overlap=short bonds
- low hardness
- brittle, not ductile
- doesnt conduct
- low melting/boiling points
- solubility is maybe (depends on polarity)
covalent network bulk physical properties
- highly regular arrangements
- shape of arrangements affect hardness, typically high hardness
- doesnt conduct
- high melting/boiling pts
- poor solubility
metallic bulk physical properties
- lustrous
- ductile,malleable
- high electrical and thermal conductivity
- low solubility
- low hardness
larger ionic charge (kf < al2o3)
more soluble, lower melting pt, more brittle
smaller ionic radius (lif<kcl)
lower metling pt, more soluble, more brittle
carbon allotropes
sp3c (diamond is hard and chemmically resistant), sp2c (graphite forms hard sheets that arent well bonded tgt)
malleability/ductility
nuclei can shift bc its attracted to e- sea, not eo
conduction
e- in the e- sea are delocalized, they arent stuck to any nuclei and r indistinguishable
- when voltage applied, e- can come in and leave simultaneously w no change ot the e- sea
lustre
atoms arrange themselves into crystal to allow them to be smooth, e- sea allows e- to absorb almost all energies of lightbc all light is absorbed and emitted
crystal grains
many small crystal arrangements within a lump of metal
what is crystal grain size affected by
rate of cooling of molten metal
- slow=large grains
- fast=small grains
large crystal grains results in
more metallic, more malleable, conductive, etc.
small crystal grains result in
harder metals, more resistant, brittle, etc.
quenching
process of cooling the outside rapidly
tempering
slow cooling for large crystal grains
interstitial alloys
small atoms fit in bw the crystal grains to provide hardness
substitutional alloys
same-ish size atoms take place of usual element in crystal
intramolecular forces
keep atoms tgt to make molecules
intermolecular forces
keep molecules tgt to make bulk substances
