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# Metal properties

## Metallic bonding

In metals, the atoms are held together by metallic bonding. Metallic bonding is responsible for many properties of metals.

Metal atoms tend to lose electrons, forming positively charged cations.

The electrons lost by the metal atoms become delocalised. They do not belong to any specific atom but are shared by all the atoms around.

The delocalised electrons can be found anywhere in the space between the cations.

The electrons float between the cations like water around rocks. This is why the free electrons are collectively called a sea of electrons.

The electrons in the electron sea are attracted to the cations because of electrostatic forces. The metallic bond is strong as the positive and negative particles are strongly attracted to each other.

## Melting and boiling point

Metal atoms form strong bonds, therefore metals have high melting and boiling points.

Large amounts of energy is required to overcome the electrostatic attractions holding the positive cations and negative electrons together.

Metals tend to have higher melting and boiling points than non-metals because non-metals require less energy to separate.

Metals tend to be solids at room temperature, with exceptions such as mercury ($\ce{Hg}$).

Metallic bonds are stronger when more electrons are in the sea because the electrostatic attraction is greater. Metals that lose more electrons to the sea therefore have higher melting and boiling points.

Aluminium melts at a higher temperature than sodium because aluminium atoms each lose three electrons to the sea while sodium atoms each lose just one electron.

## Conductivity

Overhead power lines transmit electricity over long distances. The wires are usually made of metals such as aluminium.

Metals are good conductors of heat and electricity. This is because they have a sea of delocalised electrons.

Conductors of electricity are materials that can carry electric current. To conduct electricity, charged particles (such as electrons) in the material must be able to move freely.

Metals are able to conduct electricity as they have delocalised electrons, which are negatively charged particles that can move freely.

Metals are also good conductors of heat because of the free moving electrons. These electrons readily allow for the flow of kinetic energy, which results in heat transfer.

## Malleability

Malleable materials can be bent without breaking and ductile materials can be stretched into wires.

Metals are malleable and ductile because of the structure of metallic bonds.

The atoms in the metallic structure exist in planes. These planes of atoms can slide past each other because there is no direct atom-to-atom bonding.

The metallic bond does not break when bent or stretched because the electrostatic attraction between the electron sea and the cations is still present.

Their malleability distinguishes metals from ionic compounds, which break if they are bent.

Ionic compounds are not malleable and ductile because they have bonds between specific particles.

In metals, there are no bonds between specific particles, just the overall attraction between the sea and cations.