Chemistry - Metallic Bonding

Metallic bonding

-Metals bond between the same atoms (not necessarily different elements)

-Electrostatic attraction between the positive nuclei of the metal and a sea of delocalised electrons

-An example of non-directional bonding as the electrons are not bonded to any specific nucleus. They are free to move

Properties

Conduct Electricity (solid/liquid)

Conduct heat (solid/liquid)

Malleable and ductile

High melting/boiling points

Hard

Conduct Electricity (solid/liquid)

-Metals are good conductors

-They have non-directional bonding, electrons are free to shift and move when exposed to electrical current

-easily pass it through collisions and vibrations

Conduct heat (solid/liquid)

-Nuclei are tightly packed and electrons transfer energy easily through nuclei

-easily pass it through collisions and vibrations

Malleable and ductile

-Metals can be shaped due to their non-directional bonds

-movement of electrons or re-arrangement of nuclei does not disrupt the bonding within metal, allowing metal to be shaped without breaking

High melting/boiling points

-most metals will have high melting/boiling points due to strong attraction between electrons and nuclei

-high amounts of energy to separate

Hard

-Due to strong attraction between a nucleus and electrons.

-Pulls in the nucleus and electrons, making the bond dense, hence hard

Reactivity:

-Metals will react with water, oxygen and acids

-general trend : group 1 > group 2 > transition metals

-increases down group due to electronegativity/ionisation energy

Alloys

-mixtures of metals that are created to negate properties of particular metals (i.e. increase strength, reduce malleability, etc)

-other atoms are different sizes to metal atoms which disrupts 3D crystal structure of metal lattice

-Alloys will generally have increased strength as the other atoms make it more difficult for layers of cations to slide over others

=Brittleness will also increase as layers can’t shift as easily

*table 4.4.3 pg91 for examples

nanomaterials:

-Nanomaterials help change the properties of the metal compared to its ‘normal’ bulk form

-nanotubes

-nanoparticles

-nanowires

-nanorods