4.2 - Covalent Bonding Flashcards

1
Q

What is covalent bonding?

A

Covalent bonding is the electrostatic attraction between protons in two nuclei and a shared pair of electrons between them.

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2
Q

Why do simple molecular substances have low boiling points?

A

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

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3
Q

Can simple molecular substances conduct electricity?

A

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.

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4
Q

Properties of C60 fullerene?

A

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.

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5
Q

Examples of giant covalent substances?

A
  • diamond
  • graphite
  • silicon dioxide
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6
Q

Properties of diamond?

A
  1. Every C makes 4 covalent bonds
  2. Tetrahedral shape
  3. Strong, grid-like arrangement
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7
Q

Why do giant covalent substances sublime at a high temperature?

A
  1. Covalent bonds are very strong
  2. There are lots of bonds in the giant lattice
  3. Lots of energy is required to break all the bond
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8
Q

Can diamond conduct electricity?

A

It cannot conduct electricity, because there are no freely-moving charged particles.

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9
Q

Properties of graphite?

A
  1. Layers of hexagons of C atoms
  2. Every C makes 3 covalent bonds
  3. Weak intermolecular forces (IMFs) between layers
  4. Delocalised electrons inside each layer.
  5. It is soft and slippery
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10
Q

Why is graphite soft and slippery.

A

It is soft and slippery because the layers can slide easily

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11
Q

Can graphite conduct electricity?

A

It can conducts electricity, because inside the layers the delocalised electrons can move freely

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12
Q

Properties of silicon dioxide?

A
  1. Every Si makes 4 covalent bonds
  2. Every O makes 2 covalent bonds
  3. Tetrahedral shape
  4. Strong, grid-like arrangement
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13
Q

Can silicon dioxide conduct electricity?

A

no

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