Atomic Structure & Bonding

Question 1

What is the engineering process for developing materials?

Answer 1

processing, structure, properties, performance

Question 2

Name 5 properties of materials

Answer 2

Density, mechanical, electrical, thermal, optical, magnetic, corrosive/chemical

Question 3

Name the main 4 (technically 5) materials categories

Answer 3

metals, ceramics, polymers, composites, advanced materials

Question 4

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

Answer 4

Metals

Question 5

Metal material is composed of one or more _____ elements with small quantities of ______ elements

Answer 5

a) metallic
b) nonmetallic

Question 6

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

Answer 6

Ceramics

Question 7

Ceramic material is a ______ of metallic and non-metallic elements

Answer 7

composite

Question 8

Ceramic materials have what type of bonds?

Answer 8

Ionic or covalent bonds

Question 9

Metals have what type of bonds?

Answer 9

Metallic

Question 10

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

Answer 10

Polymers

Question 11

A polymer is a class of _____ that consists of a repeating structure of >~20 units

Answer 11

macromolecule

Question 12

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

Answer 12

composites

Question 13

What is the trend for electronegativity on the periodic table?

Answer 13

lower=left, bottom
higher=right, up

Question 14

What are the 4 types of atomic bonds?

Answer 14

ionic, covalent, metallic, and van der waals forces

Question 15

The deeper the “energy well” of an atomic force, indicates what?

Answer 15

Bond energy

Question 16

Temperature is a measure of the ____ of atoms

Answer 16

mobility

Question 17

True or False: Materials with a higher melting temperature have a higher bond strength

Answer 17

True

Question 18

True or False: A steeper energy well indicates a higher melting temperature

Answer 18

True

Question 19

Which has a steeper energy well (and therefore a higher melting point): polymers, or metals & ceramics? Why?

Answer 19

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

Question 20

Which bond type “gives” electrons?

Answer 20

Ionization

Question 21

Which bond type “shares” electrons?

Answer 21

covalent

Question 22

Which bond type has partial ions?

Answer 22

polar covalent

Question 23

Which bond type shares loosely held electrons? hint: “electron sea”

Answer 23

metallic

Question 24

What 3 types of bonds are primary bonds?

Answer 24

Ionic, covalent, metallic

Question 25

What bond is a secondary bond?

Answer 25

Van der waals

Question 26

Ceramics have what combination of bonds

Answer 26

Ionic and Covalent

Question 27

Polymers have what combination of bonds?

Answer 27

Covalent and vdW