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CH1012
BANDS
The
energies of the MOs in a solid are very close together and are grouped into Bands
which gives
rise to the name Band Structure which is used
to describe the electronic structure of solids.
rise to the name Band Structure which is used
to describe the electronic structure of solids.
1. Valence band (formed from occupied MOs)
2. Conduction band (formed from empty MOs)
Metals.
In a metal
electrons can move easily from one energy
level to another resulting in high
electrical and thermal conductivity and so metals have the band structure of a conductor.
Bonding
is very delocalised in a metal and it is therefore Ductile
(may be drawn into wires) and Malleable (may be hammered
into sheets).
A wide
range of light energy can be absorbed and re-emitted, moving electrons from one band to another, metals are therefore Lustrous (shiny).
