FEEG1002 Materials - Lecture 1: Atoms, Bonding and the Origins of Material Properties

Vocabulary flashcards covering the atomic structures, types of primary and secondary atomic bonding, interatomic potential curves, material class properties, and analytical methods from FEEG1002 Materials Lecture 1.

Atomic Number ($Z$)

The number of protons found in the nucleus of an atom.

Atomic Weight

The weighted average of the atomic masses of an atom's naturally occurring isotopes, accounting for the combined mass of protons, neutrons, and electrons.

Energy-Dispersive X-ray Spectroscopy (EDX)

An elemental microanalysis technique where an incoming high-energy electron beam ejects an inner-shell electron, causing an outer-shell electron to fill the vacancy and emit a characteristic X-ray unique to that element.

Equilibrium Interatomic Spacing ($r_0$)

The distance between two atom centers at which the net interatomic force is zero ($F_N = F_A + F_R = 0$), where the attractive force ($F_A$) equals the repulsive force ($F_R$).

Bonding Energy ($E_0$)

The potential energy minimum occurring at the equilibrium spacing $r_0$, representing the net energy required to separate adjacent atoms to an infinite distance.

Primary Bonding

Major chemical bonding that enables atoms to achieve filled and stable electron orbitals through electron transfer, localized electron sharing, or large-scale electron delocalization.

Ionic Bonding

A primary bond type formed by the transfer of valence electrons from metallic (electropositive) atoms to nonmetallic (electronegative) atoms, creating mutually attracting charged ions held by coulombic forces.

Covalent Bonding

A primary bond type formed when adjacent atoms achieve stable outer-shell configurations by sharing valence electrons that remain firmly localized in the region between the bonded nuclei.

Metallic Bonding

A primary bond characterized by positive ion cores embedded in a freely moving, delocalized "sea" of valence electrons distributed over large interatomic distances.

Fluctuation-Induced Dipole Bond

A type of secondary van der Waals bonding resulting from temporary, asymmetric fluctuations in the spatial distribution of an atom's electron cloud relative to its nucleus.

Hydrogen Bonding

A strong form of secondary bonding that occurs between molecules possessing permanent dipoles formed by covalently bound hydrogen atoms (e.g., in $NH_3$ and $H_2O$).

Properties of Metals (Bonding Origins)

Material characteristics arising from metallic bonding, including high thermal/electrical conductivity (free valence electron sea), ductility and high strength (dislocation motion allowed), alloy formation, magnetism, and lustrous appearance.

Properties of Polymers (Bonding Origins)

Material characteristics featuring thermal/electrical insulation (localized electrons), low density (molecular packing), and low melting temperatures/strengths because strong covalent intrachain bonds coexist with weak secondary (van der Waals or hydrogen) interchain bonds.

Properties of Ceramics (Bonding Origins)

Material characteristics resulting from strong ionic or covalent bonds, including thermal/electrical insulation (bound electrons), high hardness and brittleness (dislocation motion prevented), high melting temperatures, and chemical inertness.

Granta EduPack

A materials engineering software package containing structured property databases used for systematic material and manufacturing process selection.

Young's Modulus vs. Electrical Resistivity Property Chart

A material property map showing technical ceramics and metals possessing high stiffness with low electrical resistivity for metals, contrasting with polymers exhibiting low stiffness and high electrical resistivity.

Fracture Toughness vs. Tensile Strength Property Chart

A material property map demonstrating that metals and alloys typically combine high tensile strength with high fracture toughness, while technical ceramics exhibit high strength but lower fracture toughness.