Metallic bonding
A more complex model is needed to explain the bonding in metalShiny element that is a good conductor of electricity and heat, and which forms basic oxides..
This model represents metal crystals as being made up of positive metal ionElectrically charged particle, formed when an atom or molecule gains or loses electrons. surrounded by a sea of negative electronSubatomic particle, with a negative charge and a negligible mass relative to protons and neutrons.. The electrostatic forceA force of attraction between particles with opposite charges. attraction between these opposite charges creates the metallic bondingBonding in metal elements consisting of a giant structure of metal atoms and their delocalised electrons moving between them.. The force of this attraction is very strong.
The sea of electrons is mobile. If a potential differenceThe potential difference (or voltage) of a supply is a measure of the energy given to the charge carriers in a circuit. Units = volts (V). This is the voltage between two points that makes an electric current flow between them. is applied across a piece of metal, the electrons will move, carrying an electrical current. This is why metals are good conductors of electricity.
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Explaining properties of metals
The giant structure of metals and metallic bonding explain their properties.
Property | Explanation |
Strong high melting point | A large amount of energy is needed to overcome the large number of strong metallic bonds |
Hardness | Metallic bonds are very strong so the giant metallic structure is strongly held together |
Malleable (can be shaped); ductile (can be drawn into thin sheets or wires) | Layers of metal ions can slide over each other when forces are applied |
Good conductors of heat and electricity | Electrons in the 'sea' of electrons are free to move |
Property | Strong high melting point |
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Explanation | A large amount of energy is needed to overcome the large number of strong metallic bonds |
Property | Hardness |
---|---|
Explanation | Metallic bonds are very strong so the giant metallic structure is strongly held together |
Property | Malleable (can be shaped); ductile (can be drawn into thin sheets or wires) |
---|---|
Explanation | Layers of metal ions can slide over each other when forces are applied |
Property | Good conductors of heat and electricity |
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Explanation | Electrons in the 'sea' of electrons are free to move |
Question
Why are group 1 metals soft and why do they have low melting points?
They have weaker metallic bonds than other metals. Less energy is needed to overcome these bonds than in other metals.