4.2 - Covalent Bonding Flashcards
What is covalent bonding?
Covalent bonding is the electrostatic attraction between protons in two nuclei and a shared pair of electrons between them.
Why do simple molecular substances have low boiling points?
Although simple molecules contain very strong covalent bonds, there are also weak intermolecular forces (IMFs) between the molecules.
When simple molecular substances boil, it’s the weak IMFs which break
Can simple molecular substances conduct electricity?
Electrical conductivity requires charged particles that can move freely. But in a simple molecular substance, there aren’t any charged particles so simple molecular substances never conduct electricity.
Properties of C60 fullerene?
1) It’s a soft and slippery solid because the molecules can roll over each other easily.
2) It is an electrical insulator because the molecules are neutral.
Examples of giant covalent substances?
- diamond
- graphite
- silicon dioxide
Properties of diamond?
- Every C makes 4 covalent bonds
- Tetrahedral shape
- Strong, grid-like arrangement
Why do giant covalent substances sublime at a high temperature?
- Covalent bonds are very strong
- There are lots of bonds in the giant lattice
- Lots of energy is required to break all the bond
Can diamond conduct electricity?
It cannot conduct electricity, because there are no freely-moving charged particles.
Properties of graphite?
- Layers of hexagons of C atoms
- Every C makes 3 covalent bonds
- Weak intermolecular forces (IMFs) between layers
- Delocalised electrons inside each layer.
- It is soft and slippery
Why is graphite soft and slippery.
It is soft and slippery because the layers can slide easily
Can graphite conduct electricity?
It can conducts electricity, because inside the layers the delocalised electrons can move freely
Properties of silicon dioxide?
- Every Si makes 4 covalent bonds
- Every O makes 2 covalent bonds
- Tetrahedral shape
- Strong, grid-like arrangement
Can silicon dioxide conduct electricity?
no
