4.2 Covalent Bonding Flashcards
Covalent Bonding
The electrostatic attraction between shared electrons and protons in nuclei of atoms
What are covalent bonds formed between?
Non-metals
Simple molecule
A small group of atoms held together by covalent bonds
Dot Cross Diagram
An atom will make a shared pair for each electron missing from its outer shell, some molecules contain double or triple pairs
Simple Molecular Substances: Low boiling point
- Weak intermolecular forces don’t require much energy to break (although they have strong covalent bonds they also have weak intermolecular forces)
- Higher mass = higher boiling point
Simple Molecular Substances: Conductivity
In simple molecular substances, there is no free to move electron and no charged particles
Allotrope
Made of the same element, but have different structures and properties
Fullerene (C60) Properties
- Simple molecular
- Low boiling point weak intermolecular forces (high molecular mass)
- High boiling point (large molecule with more atoms)
- Soft and Slippery (molecules can roll over each other
- Insulator as molecules are neutral
Fullerene uses and bonded
Each carbon atom is bonded to three others, uses = Solid Lubricant
Diamond uses and bonded
Each carbon atom is bonded to four others, tetrahedral shape strong, uses = Drill Bits
Diamond/Silicone Dioxide Properties
- Giant Covalent
- High melting point, lots of strong covalent bonds require lots of energy to overcome
- Hard, lots of strong covalent bonds
- Non-conductive, no charged particles
Graphite Properties
- Giant covalent
- High melting point, lots of strong covalent bonds require lots of energy to overcome
- Soft and Slipery, weak bonds between layers let them slide over each other
- Conductive, every carbon atom has a spare electro. that becomes delocalised
Graphite uses and bonded
Each carbon atom is bonded to 3 others in layers, use = pencils and solid lubricant
