C4 - Ionic and covalent bonding
- Created by: Naomi
- Created on: 23-01-13 17:42
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- Ionic and covalent bonding
- Why do atoms form bonds?
- Atoms with an outer shell of eight electrons have a stable electronic structure
- Atoms want to have a full outer shell and be stable
- Atoms can be made stable by:
- Transferring electrons (ionic bonding)
- Sharing electrons (covalent bonding)
- Atoms can be made stable by:
- Ionic bonding
- Ionic bonding happens between a metal and a non metal
- Metal atoms lose electrons to get a stable electronic structure
- If an atom loses electrons, a positive ion is formed. This is because there are more protons than electrons
- Non-metal atoms gain electrons to get a stable electronic structure
- If atoms gain electrons a negative ion is formed. This is because there are more electrons than protons
- During ionic bonding the metal atom becomes a positive ion and the non-metal becomes a negative ion
- The positive and negative ions then attract one another
- Metal atoms lose electrons to get a stable electronic structure
- They form giont ionic lattices and are always solid
- Positive ions have a strong electrostatic attraction to the negative ions
- They have high melting points as there are strong attractions between positive and negative ions
- They cannot conduct electricity when solid because the ions cannot move, so there are no free elecrons
- They conduct electricity when molton or in a solution because the ions are free to move
- Ionic bonding happens between a metal and a non metal
- Covalent bonding
- Non metals can share electron pairs between atoms, this is known as covalent bonding
- They leave no free electrons so the substance cannot conduct water
- Some ions (charged particles) are made from several atoms joined together. They will still form ionic compounds
- Carbonate: CO
- Sulphate: SO
- Nitrate: NO
- Ammonium: NH
- Hydroxide: OH
- When you use these ions put them in brackets if you need more than one of them
- Why do atoms form bonds?
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