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Topic 4: bonding - Coggle Diagram
Topic 4: bonding
Intermolecular forces
London dispersion force (non-polar, weakest intermolecular force)
Permanent dipole-dipole force (polar molecules, also contain London dispersion force)
Hydrogen bonds (hydrogen bonds with oxygen, hydrogen or fluorine)
Straight chain molecules can pack closer together than branched molecules, creating more points of contact between molecules, result in London dispersion force
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Temporary/instantaneous dipole(mobile clouds of changing negative charge)(induced dipole,
Covalent structure
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Valence shell electron pair repulsion theory (VSEPR) can be used to predict the shape of molecule.
- Electron pair around the central atom repel each other
- Bonding pairs & lone pairs arrange themselves to be as far apart as possible.
- Draw the lewis structure
- Determine the electron domain geometry and molecular geometry.
- Consider the repulsion by the lone pairs and bond angles.
Repulsion between electron pairs increase from: lone and lone pairs, lone and bond pairs, bond and bond pairs
Resonance structure occurs when more than one valid Lewis structure can be drawn for a particular molecule
Giant covalent network (allotrope-2 or more crystalline forms of the same element, different bonding structure
Diamond
Tetrahedron, high melting/boiling point, hard, hybridisation: SP3
Graphite
2-D network formed of hexagonal rings of carbon atoms, delocalised electrons--> conduct electricity---> electrode
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Slippery--> pencil, lubricant.
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Graphene
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Very good electrical conductor. Best thermal conductivity(electron travel on a single layler), Very flexible
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Fullerenes
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Uses: lubricant, nanotubes
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Metallic bonding: Electrostatic attraction between a lattice of positive ions and delocalised electrons./ A lattice of cations surrounded by a sea of electrons
The strength of the metallic bond is determined by 1. The number of delocalized electrons 2. The charge on the cation 3. The radius of the cation
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Covalent bonding
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Atoms that lack the necessary electrons to form a stable octet are most likely to form covalent bonds.
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Coordinate covalent bonds occur when one atom donates both of the electrons that are shared between two bonds.
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