Problem 13 - Chemistry The Central Science

Question

What kinds of attractive forces exist between particles (atoms, molecules, or ions) in (a) molecular crystals, (b) covalent-network crystals, (c) ionic crystals, (d) and metallic crystals?

Step-by-Step Solution

Answer

In (a) molecular crystals, the attractive forces are van der Waals forces or London dispersion forces caused by temporary dipoles in molecules. In (b) covalent-network crystals, strong covalent bonds hold atoms together in a large 3-dimensional network. In (c) ionic crystals, the attractive forces are ionic bonds or electrostatic forces between oppositely charged ions. In (d) metallic crystals, the attractive forces are metallic bonds, where metal atoms share valence electrons to create a "sea" of mobile electrons surrounding positively-charged metal ions.

Step 1: Molecular Crystals

In molecular crystals, the attractive forces between particles are known as van der Waals forces or London dispersion forces. These forces are weak and arise due to temporary dipoles in the molecules, caused by fluctuations in electron distribution.

Step 2: Covalent-Network Crystals

In covalent-network crystals, strong covalent bonds hold the atoms together in a large 3-dimensional network. These crystals are characterized by their strong, rigid structure and high melting and boiling points.

Step 3: Ionic Crystals

In ionic crystals, the attractive forces are known as ionic bonds or electrostatic forces. These forces are formed between oppositely charged ions, such as when a positively-charged metal ion interacts with a negatively-charged nonmetal ion.

Step 4: Metallic Crystals

In metallic crystals, the attractive forces are known as metallic bonds. These bonds occur when metal atoms share their valence electrons to create a "sea" of mobile electrons that surround the positively-charged metal ions. This creates a strong bond between the metal atoms, but also allows for the excellent conductivity of electricity and heat in metallic crystals.