Section 6.4Metallic Bonding
=The Sea of Electron Model=
Section 6.4Metallic Bonding
=The Sea of Electron Model=
Recall, metals form only positive ions...
Recall, metals form only positive ions...This is because they have a weak hold onto their valence electrons.
Consequently, all metal solid contain a "sea of electrons"
Consequently, all metal solid contain a "sea of electrons"(aka, delocalized electrons)
Consequently, all metal solid contain a "sea of electrons"(aka, delocalized electrons)
that surround the metal cations.
Metallic bond: the attraction between the metal cations and
the sea of electrons.
This is why metals can be deformed without breaking...
This is why metals can be deformed without breaking...
This is why metals can be deformed without breaking...
the sea of electrons movewith the deformation!
Properties of metals:
Properties of metals:•Good conductors of heat and
electricity.
Properties of metals:•Good conductors of heat and
electricity.•Malleable (can be reshaped).
Properties of metals:•Good conductors of heat and
electricity.•Malleable (can be reshaped).•Ductile (can be drawn into
wires).
Properties of metals:•Good conductors of heat and
electricity.•Malleable (can be reshaped).•Ductile (can be drawn into
wires).•Lustrous (shiny; electrons
absorb and re-emit light)
Properties of metals:•Good conductors of heat and
electricity.•Malleable (can be reshaped).•Ductile (can be drawn into
wires).•Lustrous (shiny; electrons
absorb and re-emit light)•High melting and boiling points.
Q: Why are group 1 and 2 metals soft, but most of the transition metals quite hard?
Transition Metals
Number of delocalized electrons
Group 2 MetalsGroup 1 Metals
Transition Metals
Number of delocalized electrons
Soft Group 2 MetalsGroup 1 Metals
Hard
Very Soft
1
Transition Metals
Number of delocalized electrons
Soft Group 2 MetalsGroup 1 Metals
Hard
Very Soft
21
Transition Metals
Number of delocalized electrons
Soft Group 2 MetalsGroup 1 Metals
Hard
Very Soft
2+21
Transition Metals
Number of delocalized electrons
Soft Group 2 MetalsGroup 1 Metals
Hard
Very Soft
2+21
Transition Metals(also smaller!)
Number of delocalized electrons
Soft Group 2 MetalsGroup 1 Metals
Hard
Very Soft
Alloy:
Alloy: A mixture of metallic elements, held together by metallic bonds.
Examples