06 - Structure of materials

Question 1

what is macrostructure

Answer 1

structure as examined with the naked eye or under low magnification (may itself include different levels of structure)

Question 2

what is Microstructure

Answer 2

structure as observed using optical microscopy

Question 3

what is substructure

Answer 3

structure obtained by using a microscope with a much higher magnification and resolution than the optical microscope ex: scanning electron microcopy

Question 4

what is a crystal structure

Answer 4

• atoms situated in an orderly and repetitive arrangement which occupies space
• provides the details of the atomic arrangement withing a cell
• sufficient to describe the arrangement of a frew atoms within the unit cell

Question 5

what is electronic structure

Answer 5

• electrons in the outermost orbitals of individual atoms tat constitute the solid
• spectroscopic techniques are very useful in determining electronic structure

Question 6

what is nuclear structure

Answer 6

studied by nuclear spectroscopic techniques, such as nuclear magnetic resonance

Question 7

what is molecular structure

Answer 7

• spatial arragement of small groups of atoms which are strongly joined together within the group or molecule

Question 8

which structure exerts a major influence on the mechanical and physicial properties of the material

Answer 8

electronic structure

Question 9

which structure exert a strong influence on material behaviour

Answer 9

molecular structure and crystal structure

Question 10

what is strongly affected by molecular and crystal structure

Answer 10

the deformation behaviour of a material *its response to applied loads and forces)

Question 11

what is an isomer

Answer 11

• if atoms in a molecule have the capability of forming different geometrical or structural arrangements without a change in chemical composition

Question 12

what is polymorphism

Answer 12

in a crystalline material the ability to transform from one type of geometrical configuration to another

Question 13

the properties of engineering materials are intimately lined to how closely the molecular or crystal structures resemble

Answer 13

a perfect structure

Question 14

what is a perfect structure

Answer 14

• no atoms or ions are missing from their appointed positions
• the respective structure exhibits no geometrical deviations from perfection