Covalent Bonding
- Created by: EmilyRoseC
- Created on: 22-01-17 11:38
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- Covalent Bonding
- Enthalpy
- + nuclei are attracted to e- densite. + nuclei also repel each other
- The distance between the 2 nuclei is where attractive and repulsive forces are balances
- Higher electron density = stronger attraction between atoms & lower bond length
- Evidence
- Good thermal conductors = vibrations easily travel through lattice
- Often very hard = strong bonds in the lattice
- Insoluble = covalent bonds mean atoms are more attracted to atoms in the lattice than the solvents
- High melting points = need to break a lot of bonds to melt it
- Can't conduct electricity = no free charged ions or electrons
- Bonding
- 2 atoms share electrons so they both have full outer shells
- The strong electrostatic attraction between the bonding nuclei and the electrons in the bonds
- Giant Structures
- Each atom is covalently bonded to other atoms in the structure
- Have a network of covalently bonded atoms = high electrostatic attraction
- Covalent bonding can form simple structures or giant lattices
- Dative Bonds
- One atom donates both electrons to a bond
- Ammonium ions are formed by dative covalent bonds. Nitrogen atom donates a pair of e- to H+
- Graphite
- Carbon atoms form sheets
- Each carbon atom shares 3 e- with other atoms in structure, 4th can move between sheets
- One sheet = joined in hexagons & 1 atom thick
- Can conduct as delocalised electrons can move along the sheet
- Incredibly strong, transparent and light
- Enthalpy
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