Atomic Structure & Bonding Flashcards
What is the engineering process for developing materials?
processing, structure, properties, performance
Name 5 properties of materials
Density, mechanical, electrical, thermal, optical, magnetic, corrosive/chemical
Name the main 4 (technically 5) materials categories
metals, ceramics, polymers, composites, advanced materials
What category describes this material?
–atoms arranged in a regular repeating structure
–relatively good strength
–high density
–malleable or ductile: high plasticity
–resistant to fracture: tough
–excellent conductors of electricity
–opaque to visible light
–shiny appearance
Metals
Metal material is composed of one or more _____ elements with small quantities of ______ elements
a) metallic
b) nonmetallic
What category describes this material?
–Except for glasses, atoms are regularly arranged (crystalline)
–lower density than most metals
–often stronger than metals
–low resistance to fracture: low toughness or brittle
–low ductility or malleability: low plasticity
–high melting point
–poor conductors of electricity
–single crystals are transparent
Ceramics
Ceramic material is a ______ of metallic and non-metallic elements
composite
Ceramic materials have what type of bonds?
Ionic or covalent bonds
Metals have what type of bonds?
Metallic
What type of category describes this material?
–composed primarily of C and H
–Generally produced from fossil fuels
–low melting temperature
–easily processed
–semicrystalline/amorphous morphology
–most are poor conductors
–many have high plasticity
–a few have good elasticity
–some are transparent, some are opaque
Polymers
A polymer is a class of _____ that consists of a repeating structure of >~20 units
macromolecule
What category describes this material?
–composed of two or more different materials
–properties depend on amount and distribution of each type of material
–collective properties more desirable than possible with any individual material
composites
What is the trend for electronegativity on the periodic table?
lower=left, bottom
higher=right, up
What are the 4 types of atomic bonds?
ionic, covalent, metallic, and van der waals forces
The deeper the “energy well” of an atomic force, indicates what?
Bond energy
Temperature is a measure of the ____ of atoms
mobility
True or False: Materials with a higher melting temperature have a higher bond strength
True
True or False: A steeper energy well indicates a higher melting temperature
True
Which has a steeper energy well (and therefore a higher melting point): polymers, or metals & ceramics? Why?
Metals and ceramics. Metallic bonds are stronger and harder to break, meaning more energy needs to be added to move the bonds enough to break
Which bond type “gives” electrons?
Ionization
Which bond type “shares” electrons?
covalent
Which bond type has partial ions?
polar covalent
Which bond type shares loosely held electrons? hint: “electron sea”
metallic
What 3 types of bonds are primary bonds?
Ionic, covalent, metallic
What bond is a secondary bond?
Van der waals
Ceramics have what combination of bonds
Ionic and Covalent
Polymers have what combination of bonds?
Covalent and vdW
