Stage 1 Chemistry Bonding L Notes
Topic One: Bonding
‘Bonding is the electrostatic attraction between…’
Primary (strongest) Secondary
Metallic Ion-dipole
Ionic Hydrogen bonding
Covalent molecules Dipole /dipole
Covalent network (giant covalent) Dispersion forces
- Primary bonds are strongest
Topic 1.1 Metallic Bonding
Metallic Bonds
- Occur between metals
- The electrostatic attraction between the cations (+ve) and the delocalised electrons (-ve)
- Example: Na – valence electron is donated to a common pool of e- . This results in Na+ and a
delocalised e- .
- Delocalised = mobile
Metallic Bonding: MP AND BP
Period three
Element Radius (pm) Ionic charge m.p (C) b.p (C)
Sodium 116 1+ 97.9 883
Magnesium 86 2+ 650 1090
Aluminium 68 3+ 660 2519
Metallic Network: Malleability and Ductility
In metallic lattice:
- Electrons are free to move and positive ions are not bound to each other
If force is applied:
- Layers can slide over each other
- If the structure becomes deformed, it is able to maintain charge balance
Metallic network: Conduction
Free movement of electrons in metal conducts both heat and electricity through the structure
- Electrons transfer heat energy away from the heat source
- Electrons move when a potential difference is applied towards the positive terminal of the power
supply.
Bonding Between Atoms
- The physical properties of metallic elements can be explained using the model for metallic bonding.
, Stage 1 Chemistry Bonding L Notes
Classifying Materials: Metallic
Metallic materials in which metal atoms are formed by metallic bonds.
There is a strong attractive force between a free moving delocalised electron and a metal cation.
The structure is continuous, with the cations in a recurring geometric patter, known as a 3D metallic lattice.
Since they are in a lattice, they are not mobile.
Strong forces between particles
- High melting point (strong attraction)
Delocalised electrons free to move
- High conductivity
Metallic Bonding: Strength
- Metallic bonds are strong
- Results in hard, high melting point/boiling point materials
Melting Point Response to Electrical Conductivity
Force Solid Molten Dissolved
Generally high Bend, fold, formed Does conduct Does conduct Metals do not
(strong bond). into wires without electricity. electricity. dissolve in H2O.
breaking.
3+ is likely to have a Because they have Because they have
stronger metallic Malleability: Al, Au. delocalised delocalised
bond. 3+ tends to Ductility: Cu, Fe. electrons (mobile) electrons and
be small, 1+ tends mobile positive ions.
to be large.
- Metal atoms will release / donate their valence electrons into a common pool of delocalised electrons.
- Metallic bonds are the electrostatic attraction between metal cations (+ve) and delocalised valence
electrons.
- Bent / folded distorts lattice of cations but the delocalised electrons adjust their position so no
repulsion occurs. It gets warmer due to friction.
Topic 1.2: Ionic Bonding
Ionic Bonds
- Between metals and non-metals
- The electrostatic attraction between oppositely charged ions i.e., cations (+ve) and anions (-ve)
- Example: Na (1s22s22p63s1) – valence e- is donated to chlorine to make 3p6 (transfer). This results in
Na+ (sodium ion) and Cl- (chloride ion)
Melting Point Response to Electrical Conductivity
Force Solid Molten Dissolved
Usually high. This is They are brittle and Does not conduct Does conduct as Does conduct as
due to the strength exist in crystal as the ions are not the ions are now the hydrated ions
of the ionic bond. form. mobile. mobile. are mobile.
- Cannot conduct electricity if not mobile.
Topic One: Bonding
‘Bonding is the electrostatic attraction between…’
Primary (strongest) Secondary
Metallic Ion-dipole
Ionic Hydrogen bonding
Covalent molecules Dipole /dipole
Covalent network (giant covalent) Dispersion forces
- Primary bonds are strongest
Topic 1.1 Metallic Bonding
Metallic Bonds
- Occur between metals
- The electrostatic attraction between the cations (+ve) and the delocalised electrons (-ve)
- Example: Na – valence electron is donated to a common pool of e- . This results in Na+ and a
delocalised e- .
- Delocalised = mobile
Metallic Bonding: MP AND BP
Period three
Element Radius (pm) Ionic charge m.p (C) b.p (C)
Sodium 116 1+ 97.9 883
Magnesium 86 2+ 650 1090
Aluminium 68 3+ 660 2519
Metallic Network: Malleability and Ductility
In metallic lattice:
- Electrons are free to move and positive ions are not bound to each other
If force is applied:
- Layers can slide over each other
- If the structure becomes deformed, it is able to maintain charge balance
Metallic network: Conduction
Free movement of electrons in metal conducts both heat and electricity through the structure
- Electrons transfer heat energy away from the heat source
- Electrons move when a potential difference is applied towards the positive terminal of the power
supply.
Bonding Between Atoms
- The physical properties of metallic elements can be explained using the model for metallic bonding.
, Stage 1 Chemistry Bonding L Notes
Classifying Materials: Metallic
Metallic materials in which metal atoms are formed by metallic bonds.
There is a strong attractive force between a free moving delocalised electron and a metal cation.
The structure is continuous, with the cations in a recurring geometric patter, known as a 3D metallic lattice.
Since they are in a lattice, they are not mobile.
Strong forces between particles
- High melting point (strong attraction)
Delocalised electrons free to move
- High conductivity
Metallic Bonding: Strength
- Metallic bonds are strong
- Results in hard, high melting point/boiling point materials
Melting Point Response to Electrical Conductivity
Force Solid Molten Dissolved
Generally high Bend, fold, formed Does conduct Does conduct Metals do not
(strong bond). into wires without electricity. electricity. dissolve in H2O.
breaking.
3+ is likely to have a Because they have Because they have
stronger metallic Malleability: Al, Au. delocalised delocalised
bond. 3+ tends to Ductility: Cu, Fe. electrons (mobile) electrons and
be small, 1+ tends mobile positive ions.
to be large.
- Metal atoms will release / donate their valence electrons into a common pool of delocalised electrons.
- Metallic bonds are the electrostatic attraction between metal cations (+ve) and delocalised valence
electrons.
- Bent / folded distorts lattice of cations but the delocalised electrons adjust their position so no
repulsion occurs. It gets warmer due to friction.
Topic 1.2: Ionic Bonding
Ionic Bonds
- Between metals and non-metals
- The electrostatic attraction between oppositely charged ions i.e., cations (+ve) and anions (-ve)
- Example: Na (1s22s22p63s1) – valence e- is donated to chlorine to make 3p6 (transfer). This results in
Na+ (sodium ion) and Cl- (chloride ion)
Melting Point Response to Electrical Conductivity
Force Solid Molten Dissolved
Usually high. This is They are brittle and Does not conduct Does conduct as Does conduct as
due to the strength exist in crystal as the ions are not the ions are now the hydrated ions
of the ionic bond. form. mobile. mobile. are mobile.
- Cannot conduct electricity if not mobile.
