Skip to main content
Ch.12 - Solids and Modern Materials
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Non è quello che usi tu?Cambia libro di testo
Capitolo 12, Problema 33a

Consider the unit cells shown here for three different structures that are commonly observed for metallic elements. (a) Which structure(s) corresponds to the densest packing of atoms?
Three cubic unit cells labeled A, B, and C, showing different atomic arrangements for metals.

Guida verificata passo dopo passo
1
Identify the type of unit cell for each structure: A, B, and C.
Determine the number of atoms per unit cell for each structure.
Calculate the packing efficiency for each type of unit cell.
Compare the packing efficiencies to determine which structure(s) have the densest packing.
Conclude which structure(s) correspond to the densest packing of atoms based on the highest packing efficiency.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
1m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Unit Cell

A unit cell is the smallest repeating unit of a crystal lattice that reflects the overall symmetry and structure of the entire crystal. It defines the arrangement of atoms in a solid and can vary in shape, such as cubic, tetragonal, or hexagonal. Understanding unit cells is crucial for analyzing the packing efficiency and density of different crystalline structures.
Video consigliato:
Percorso guidato
01:27
Simple Cubic Unit Cell

Atomic Packing Efficiency

Atomic packing efficiency (APE) refers to the fraction of volume in a crystal structure that is occupied by atoms. It is calculated by comparing the volume occupied by the atoms to the total volume of the unit cell. Higher packing efficiency indicates a denser arrangement of atoms, which is important for understanding the physical properties of metals and their stability.
Video consigliato:

Close-Packed Structures

Close-packed structures, such as face-centered cubic (FCC) and hexagonal close-packed (HCP), are arrangements where atoms are packed together as closely as possible. These structures maximize atomic density and are characterized by specific coordination numbers and packing efficiencies. Identifying these structures is essential for determining which metallic arrangements provide the densest packing.
Video consigliato:
Percorso guidato
01:42
Resonance Structures