Section 6.4 Metallic Bonding =The Sea of Electron...

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...

the sea of electrons movewith the deformation!

Properties of metals:

Properties of metals:•Good conductors of heat and

electricity.


electricity.•Malleable (can be reshaped).


electricity.•Malleable (can be reshaped).•Ductile (can be drawn into

wires).



wires).•Lustrous (shiny; electrons

absorb and re-emit light)



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


Soft Group 2 MetalsGroup 1 Metals

Hard

Very Soft

1

Transition Metals



Hard

Very Soft

21

Transition Metals



Hard

Very Soft

2+21

Transition Metals



Hard

Very Soft

2+21

Transition Metals(also smaller!)



Hard

Very Soft

Alloy:

Alloy: A mixture of metallic elements, held together by metallic bonds.

Examples

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