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Bonding - Coggle Diagram
Bonding
Covalent
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Properties
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"Like dissolves like": nonpolar substances dissolve in nonpolar solvents, polar substances dissolve in polar solvents
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Lewis Structure
Instructions: Count the total number of valence electrons, draw the skeletal positions, then add electron pairs, and finally check your structure,
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The octet rule: the tendency of atoms to gain a valence energy level of 8 electrons. More than that is 'expanding the octet rule'; less than that means the central atom is 'electron deficient'.
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VSPER Theory
The electron pairs around a central atom repel each other. To minimise this, these electron pairs arrange themselves as far apart as possible
Rules:
- All electron pairs spread out as far as possible
- lone pairs repel more strongly than bonding pairs
- Multiple bonds behave like a single bond when determining shape
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Intermolecular forces:
London dispersion forces: as electrons are constantly moving, there could be an instantaneous dipole. This can induce a dipole in the neighbouring non-polar molecule.
Dipole-dipole attractions: between the δ⁺ end of one polar molecule and the δ⁻ end of a neighbouring molecule
Dipole-induced dipole attraction: This type of attraction occurs when a polar molecule is placed near a nonpolar molecule.
Hydrogen bonding: Permanent dipole-dipole attraction. A hydrogen has to be covalently bonded to N, O, or F. There has to be a lone pair of electrons on an N, O, or F in a neighbouring molecule.
Metallic Bonding
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Once the outer electrons are delocalised, the metal atoms become positively charged. The positive charges repel each other and keep the neatly arranged lattice in place. There are very strong electrostatic orces between the cations and sea of delocalized electrons.
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Properties:
They are malleable and ductile because layers of metal ions can slide over each other when force is applied
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High MP/BP due to strong electrostatic forces of attraction which require lots of energy to overcome
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Ionic
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They form a 3D giant lattice structure. The cations and anions are attracted to each other by strong electrostatic forces.
Lattice enthalpy is the standard enthalpy change that occurs on the formation of 1 mole of gaseous ions from the solid lattice.
It is an endothermic process; the enthalpy change will always have a positive value as energy is always required to break bonds.
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Source: Boole, Richard. “Ionic Lattices | DP IB Chemistry Revision Notes 2023.” Save My Exams, 12 Dec. 2024, www.savemyexams.com/dp/chemistry/ib/23/hl/revision-notes/models-of-bonding-and-structure/the-ionic-model/ionic-lattices/. Accessed 5 Dec. 2025.