Bonding
- Created by: Rachel Wyles
- Created on: 29-01-14 16:58
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- BONDING
- Ionic bonding
- Atoms are formed when e- are transferred from one atom to another
- Electrostatic attraction holds +ve and -ve ions together = VERY STRONG
- Ionic compounds form a giant ionic lattice
- Properties
- Conduct elec' when MOLTEN or DISSOLVED but not when solid... because ions not free to move so no charge present.
- HIGH MELTING POINT due to strong electrostatic forces which are require a lot of KE to overcome
- Often dissolve in water due to the polarity of the water. -ve molecules are pulled away by water molecules causing it to dissolve
- Egs NaCl MgCl2
- Covalent bonding
- Molecules are formed when two or more atoms are covalently bonded together
- The covalent bond involved sharing e- so they have a full outer shell
- Both +ve nuclei are attracted electro statically to shared e-
- A dative covalent bond is where both e- come from the one atom eg NH4+
- Represented by an arrow coming away from donor atom
- Properties
- LOW MELTING POINT as only have to overcome weak ID ID or H bonds, not the covalent bonds
- DON'T CONDUCT ELEC' as there are no e- free to move to create a current
- Insoluble in water, polar water molecules are more attracted to each other than molecular substance
- Egs CO2 O2 N2
- Giant covalent
- HIGH MELTING POINT need to break many strong bonds which requires a lot of KE
- Insoluble in Water
- Won't conduct electricity apart from graphite- as graphite has delocalised e- and so can carry current
- Egs SiO2, Diamond
- Metallic bonding
- HIGH MELTING POINT due to strong metallic bonds - the more delocalised e- affects the mp as this means stronger bonds
- Insoluble as the strength of metallic bonds is too strong to overcome
- Will conduct elec' as the delocalised e- can carry charge
- Made of positive metal cations and sea of delocalised e- which are attracted to each other
- Egs Mg Na Al
- Ionic bonding
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