Covalent Bonding Flashcards
What is a Covalent Bond?
When two non-metals share electrons to fill their valence shells. The shared electrons joining the two atoms together causes them to bond.
Covalent molecular substances?
Covalent substances that exist in discrete molecules are called covalent molecular substances.
- Water, oxygen, CO2, Cl2, H2, NH3
- Intramolecular forces are strong, but intermolecular forces are weak, so easy to break.
Covalent molecular properties?
- Malleable
- Low MP & BP
- Form soft solids
- Do not conduct electricity
- Variable solubility
Covalent Molecular solids:
Formed by some covalent molecular substances at room temperature.
- Millions of covalent molecules are held together by weak forces of attraction to create a 3D molecular lattice.
- Low BP and MP
- Soft and brittle
- Cannot conduct electricity
Covalent Network substances:
Vast networks of covalent bonding atoms.
- Three dimensional network of covalently bonded atoms.
- Intermolecular forces strong like covalent bonding
- Continuous array of covalently bonded atoms.
Properties of Covalent network structures/substances:
- Very high MP/BP
- Brittle
- Cannot conduct electricity
- Insoluble in most solvents and water.
Allotropes:
Are different forms of the same element.
- Different properties as atoms are bonded in different arrangements which create different network substances.
Name the carbon allotropes:
- Diamond
- Graphite
- Buckminsterfullerene
- Carbon nanotubes
Buckminsterfullerene:
Is a type of fullerene, contains 60 carbon atoms, each of which is bonded to three others by two single bonds and one double bond.
- Form a sphere
- Called buckyballs
Carbon nanotubes:
A type of fullerene, cylindrical carbon molecules, transports drugs around body and as components in electrical transistors.
Diamond properties:
-Veryhard
- Cannot conduct electricity
- Hight MP/BP
Graphite properties:
- Soft and slippery - Layers can slide over each other because of weak forces of attraction
- Conducts electricity
