Chemical Bonding
- Created by: Emily Cartwright
- Created on: 29-03-14 17:40
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- Chemical Bonding
- Bond breaking is an endothermic process
- Bond forming is an exothermic process
- Melting and Boiling involve breaking bonds between particles. The stronger the bonds that have to be broken, the more energy it takes in, so the higher the melting/boiling point
- Structure and Bonding
- Metallic Bonding occurs between the atoms of metals
- Ionic Bonding occurs between oppositely charged ions
- Covalent Bonding occurs when two atoms share a pair of electrons
- Intermolecular forces are weaker bonds that attract individual molecules to one another. These forces prevent molecules from spreading out away from one another when in a solid or liquid
- Giant Structures
- A substance has a giant structure if the bonding exists throughout the whole crystal
- Giant Ionic Structures
- Strong Ionic bonds between oppositely charged ions extend everywhere through a giant ionic lattice structure. Strongs ionic bonds have to be broken to achieve melting or boiling
- Giant Metallic Structures
- Strong metallic bonds between metal atoms extend everywhere through a giant metallic lattice structure. Strong metallic bonds have to be broken to achieve melting or boiling
- Giant Covalent Structures (Giant Molecular)
- A network of strong covalent bonds extends everywhere through a crystal of the substance. Strong covalent bonds between non-metal atoms have to be broken to achieve melting or boiling
- Simple Molecular Structures
- Substances made of separate molecules, each of which contains a specific number of atoms joined together by covalent bonds
- In a solid or a liquid, the individual molecules are attracted to each other by much weaker intermolecular forces
- Only the weak intermolecular forces have to be broken to achieve melting or boiling. The strong covalent bonds remain intact, even in the gas phase
- In a solid or a liquid, the individual molecules are attracted to each other by much weaker intermolecular forces
- Substances made of separate molecules, each of which contains a specific number of atoms joined together by covalent bonds
- Ionic Bonding
- 'Ionic bonding is the electrostatic attraction between oppositely charged ions'
- Compound Ions
- Hydroxide: OH-
- Carbonate: CO3 2-
- Sulphate: SO4 2-
- Nitrate: NO3-
- Ammonium: NH4+
- There are no molecules in ionic compounds
- 'An ionic lattice is a regular array of alternating positive and negative ions'
- Properties of Ionic Compounds
- High Melting and Boiling Points
- Due to the strong electrostatic attraction between the ions in a giant lattice
- A lot of energy is needed to overcome the strong attractive force between oppositely charged ions and so enable the ions to move around
- The higher the charge on the ions, the stronger the attractive forces they will exert in an ionic lattice and so have higher melting and boiling points
- A lot of energy is needed to overcome the strong attractive force between oppositely charged ions and so enable the ions to move around
- Due to the strong electrostatic attraction between the ions in a giant lattice
- Many ionic compounds are soluble in water
- Water is polar and when a substance like sodium chloride is added to it, to the polar water molecules are attracted to the positive sodium ions and the negative chloride ions.
- The ions then bond by electrostatic attraction (ion-dipole bonds) to the water molecules. The ions are then said to be hydrated
- Water is polar and when a substance like sodium chloride is added to it, to the polar water molecules are attracted to the positive sodium ions and the negative chloride ions.
- High Melting and Boiling Points
- Bond breaking is an endothermic process
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