Bonding and shapes of molecules
- Created by: peter davenport
- Created on: 08-12-16 11:08
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- Bonding
- Metals
- Makes a lattice work of positive ions surrounded by negative electrons
- Conducts electricity because the electrons are free to move about through the metal.(delocalised)
- Because the atoms are in sheets, this makes metallic bonds very durable and can slide over each other easily when not alloyed
- Metal + Non-metals
- Generally forms giant ionic lattices
- These lattices comprise of positive ions surrounded by negative ions in a regular pattern
- Conducts electricity when molten
- This is because the ions are free to move about in the melted "soup"
- Generally forms giant ionic lattices
- Non-metal
- Bonds between non-metals are described as covalent bonds
- This is the sharing of electrons and therefore means that no ions are formed
- Can be giant macromolecules
- Examples are diamond, Graphite and silicon dioxide
- Because the bonds are all covalent there are no intermolecular forces.
- This means that they has an extremely high melting/boiling point
- Or simple molecules
- These generally have very little forces of attraction between them unless they at polar
- Examples include CH4 and HCl
- Polarity
- A molecule is polar when there is a large difference in the electronegativity
- The electronegativity of an element is a measure of the attraction between the electrons and the highly positive nucleus
- A molecule is polar when there is a large difference in the electronegativity
- These generally have very little forces of attraction between them unless they at polar
- Dative covalent bonds
- Bonds whereupon the electrons are donated by only one of the atoms
- E.G. NH4
- E.G. NH4
- Bonds whereupon the electrons are donated by only one of the atoms
- Bonds between non-metals are described as covalent bonds
- Types of attraction
- Permanant dipole-dipole
- Where the molecule is simple and has a delta negative part and a delta positive point. E.G. HCl
- Temporary dipole-dipole
- Happens when electrons randomly get close to each other in the orbit and therefore create and temporary delta positive and delta negative part
- Hydrogen Bonding
- Only happens when hydrogen is bonded to Nitrogen, Oxygen and Fluorine
- The end hydrogen of on molecule is delta positive so is attracted to the delta negative part of another molecule creating a strong bond of attraction
- Permanant dipole-dipole
- Polarity
- A molecule is polar when there is a large difference in the electronegativity
- The electronegativity of an element is a measure of the attraction between the electrons and the highly positive nucleus
- A molecule is polar when there is a large difference in the electronegativity
- Shape of molecules
- Molecule shapes are defined by the number of bonds they make
- Bond angles are defined by the number of bonds and if there are any lone pairs
- Lone pairs are unused electrons that are in the outermost shell of the atoms that contains them
- Metals
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