Question

State the type of particles that compose each of the following: (a) ionic solid (b) molecular solid (c) metallic solid

Short answer

(a) Ionic solid: ions; (b) Molecular solid: molecules; (c) Metallic solid: metal atoms.

Step-by-step solution

Understand Ionic Solids

Ionic solids are composed of positively charged ions (cations) and negatively charged ions (anions). These ions are held together by strong electrostatic forces known as ionic bonds, forming a crystalline lattice.

Understand Molecular Solids

Molecular solids consist of discrete molecules held together by weaker forces such as London dispersion forces, dipole-dipole interactions, and hydrogen bonds. These solids are typically made up of nonmetals and have low melting and boiling points.

Understand Metallic Solids

Metallic solids are composed of metal atoms. These atoms are arranged in a lattice structure and are surrounded by a "sea" of delocalized electrons. This structure allows metallic solids to conduct electricity and heat efficiently.

Key concepts

Ionic Solids

Ionic solids are fascinating structures held together by the powerful ionic bonds formed between cations and anions. Cations are positively charged ions, typically derived from metals, while anions are negatively charged ions, often from nonmetals. The interaction between these oppositely charged ions results in a strong electrostatic force, creating a stable crystalline lattice.
The arrangement leads to some unique characteristics of ionic solids:

• High melting and boiling points, due to strong ionic bonds that require significant energy to break.
• When dissolved in water, ionic solids often conduct electricity, as the ions become mobile and carry charge.
• Brittleness, which results from the shift in the lattice that causes like charges to align and repel each other, leading to material fracture.

Examples of ionic solids include common table salt (sodium chloride) and lithium fluoride. These materials epitomize the efficient energy storage and transfer capabilities that ionic bonds provide.

Molecular Solids

Molecular solids bring into play molecules as their building blocks, held together by intermolecular forces rather than strong ionic or covalent bonds. These forces include London dispersion forces, dipole-dipole interactions, and hydrogen bonds, which are generally weaker compared to ionic interactions.
As a result, molecular solids showcase some distinctive features:

• Low melting and boiling points, since the intermolecular forces are easily overcome by adding a small amount of heat.
• They do not conduct electricity due to the absence of free-moving charged particles.
• Often soft and easily damaged for the same reasons.

Common examples of molecular solids include ice (solid water) and dry ice (solid carbon dioxide). Their presence in everyday life highlights the diversity of physical properties that molecular arrangements provide.

Metallic Solids

Metallic solids comprise metal atoms arranged in an organized lattice. What makes them unique is the presence of delocalized electrons, often described as a "sea of electrons" that freely move throughout the structure. This electron sea is crucial for several key properties observed in metallic solids:

• Efficient conductivity of electricity and heat, as electrons can flow easily within the structure.
• Malleability and ductility, allowing metals to be hammered into shapes without breaking, thanks to the lattice's ability to adjust without disrupting the entire structure.
• Luster or shininess, which comes from the ability of the electron sea to reflect light.

Examples such as copper, gold, and aluminum demonstrate the remarkable versatility and strength of metallic bonds and the utility of metals in various applications, from wiring to jewelry to construction.