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Chemistry

GCSE · Edexcel

QuestionsFlashcards

Group 1
- Group 1 (Alkali Metals)
  6
- Group 1: Reactivity & Electronic Configurations
  6
Group 7
Group 0

Qualitative Analysis: Tests for Ions
Hydrocarbons
Polymers
Alcohols & Carboxylic Acids
Bulk & Surface Properties of Matter Including Nanoparticles
- Nanoparticles
  7
- Ceramics, Polymers, Composites & Metals
  5

Comparing Ionic & Covalent Compounds Flashcards

All 6 cards in this deck

Why do ionic compounds have high melting and boiling points?: Strong electrostatic forces of attraction between the oppositely charged ions; lots of energy is needed to break them.
Why can an ionic compound not conduct electricity when solid?: The ions are held in fixed positions in the lattice, so they cannot move.
When can an ionic compound conduct electricity, and why?: When molten or in aqueous solution, because the ions are then free to move.
Why do simple molecular substances have low melting and boiling points?: The forces between the molecules (intermolecular forces) are weak, so little energy is needed to separate them.
Why do simple molecular substances not conduct electricity?: They have no free electrons or ions, so there are no charged particles free to move.
True or false? When a simple molecular substance melts, its covalent bonds are broken.: False. Only the weak intermolecular forces between molecules are overcome; the covalent bonds inside each molecule stay intact.