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 valence electrons detach from individual
atoms since metals usually contain only 1-3
valence electrons and a low ionization energy
 bonding is non-directional
 no particular electron is confined to a particular
metal cation
 leaves a close packed lattice of cations in a sea of
delocalized negative electrons
 the electrostatic attraction between the
cations and sea of electrons holds the metal
together
 electrons act as a "glue" giving the substance a
definite structure
Characteristics
 strength of a metallic bond depends on…
1. number of delocalized valence electrons
 more delocalized electrons = greater
electrostatic attraction (higher MP)
2. size of cation’s charge
 stronger the charge = greater electrostatic
attraction (higher MP)
3. ionic radius
 when the metallic atom radius decreases,
the sea of negative electrons becomes
closer to the nucleus and there is a stronger
attraction to them
 therefore, melting point decreases as you go
down the periodic table
 the delocalized nature of the bonds, make it
possible:
 conduct electricity
 for the atoms to slide past each other
 this means metals are malleable and ductile
 hammered into thin sheets or shapes without
breaking
 drawn into wires
 ionic compounds would crack
 contain more than one metal and have enhanced
properties such as
 greater strength
 the presence of different atoms disturbs the regular lattice
and hinders movement
 resistance to corrosion, enhanced magnetic
properties, and greater ductility
 examples
 steel
 Fe and C -- high tensile strength but can rust
 brass
 Cu and Zn – looks cool!
 gold alloy, dental amalgam, and so on…
 metals are essential part of the world
economy
 reinforcement of concrete, wires, cars,
pipes…
 traded as commodities
 most common is iron which is in steel