CIVE 2700 QUIZ 2 (LEC 9 - 16) QUESTIONS & ANSWERS.
Electrons are shared between atoms, possess good thermal and electrical insulation properties -
(ANSWER)covalent bonds
Electrons are transferred from one atom to another - (ANSWER)Ionic bonds
Valence electrons are easily dislodged from all the atoms, behave as a "sea of electrons" -
(ANSWER)metallic bonds
What type of bonds form metals? - (ANSWER)metallic bonds
What type of bonds form inorganic solids? - (ANSWER)covalent bonds and ionic bonds
What type of bonds form organic solids? - (ANSWER)covalent bonds
What is the key difference between organic and inorganic solids? - (ANSWER)elemental composition and
the types of chemical bonds
What are organic solids primarily composed of? - (ANSWER)carbon and hydrogen
A material in which atoms are situated in a repeating or periodic array - (ANSWER)crystalline
True or False: a BCC unit cell has an atom at each corner of the cube and one at it's centre -
(ANSWER)True
True or False: a FCC atom has an atom at each corner of a cube and at the centre of each face -
(ANSWER)True
What are the 3 lattic defects? - (ANSWER)1. point
2. line
3. surface (area)
, CIVE 2700 QUIZ 2 (LEC 9 - 16) QUESTIONS & ANSWERS.
True or False: BCC and FCC structures assume the crystal is perfect (IDEAL model) - (ANSWER)True
What are the 3 types of point defects? - (ANSWER)1. vacancy defect
2. interstitial defect
3. substitutional defect
A lattic site that is missing an atom (defect) - (ANSWER)vacancy defect
Foreign atoms or ions that occupy spaces between regular lattic spaces (defect) - (ANSWER)interstitial
defect
When an atom or ion is replaced by a different atom or ion within the crystal lattice (e.g. foreign smaller
or larger atom) (defect) - (ANSWER)substtitutional defect
Defect introduced during solidification or when a metal is plastically deformed. An extra plane of atoms
inserted into a perfect crystal that move within a grain - (ANSWER)edge dislocation
Distinct region within the materials structure where the atoms or ions are arranged in a regular and
repeating crystal lattice pattern - (ANSWER)grain
interfaces between adjacent grains with different orientations of their crystal lattice - (ANSWER)grain
boundaries
Disadvantages of surface defects - (ANSWER)1. decrease elctrical and thermal conductivity
2. increase corrosion
The crystal returns to original shape when force is removed - (ANSWER)elastic
A permanent change occurs when the force is greater than the electrostatic force holding the atoms in
their lattice positions - (ANSWER)plastic
Electrons are shared between atoms, possess good thermal and electrical insulation properties -
(ANSWER)covalent bonds
Electrons are transferred from one atom to another - (ANSWER)Ionic bonds
Valence electrons are easily dislodged from all the atoms, behave as a "sea of electrons" -
(ANSWER)metallic bonds
What type of bonds form metals? - (ANSWER)metallic bonds
What type of bonds form inorganic solids? - (ANSWER)covalent bonds and ionic bonds
What type of bonds form organic solids? - (ANSWER)covalent bonds
What is the key difference between organic and inorganic solids? - (ANSWER)elemental composition and
the types of chemical bonds
What are organic solids primarily composed of? - (ANSWER)carbon and hydrogen
A material in which atoms are situated in a repeating or periodic array - (ANSWER)crystalline
True or False: a BCC unit cell has an atom at each corner of the cube and one at it's centre -
(ANSWER)True
True or False: a FCC atom has an atom at each corner of a cube and at the centre of each face -
(ANSWER)True
What are the 3 lattic defects? - (ANSWER)1. point
2. line
3. surface (area)
, CIVE 2700 QUIZ 2 (LEC 9 - 16) QUESTIONS & ANSWERS.
True or False: BCC and FCC structures assume the crystal is perfect (IDEAL model) - (ANSWER)True
What are the 3 types of point defects? - (ANSWER)1. vacancy defect
2. interstitial defect
3. substitutional defect
A lattic site that is missing an atom (defect) - (ANSWER)vacancy defect
Foreign atoms or ions that occupy spaces between regular lattic spaces (defect) - (ANSWER)interstitial
defect
When an atom or ion is replaced by a different atom or ion within the crystal lattice (e.g. foreign smaller
or larger atom) (defect) - (ANSWER)substtitutional defect
Defect introduced during solidification or when a metal is plastically deformed. An extra plane of atoms
inserted into a perfect crystal that move within a grain - (ANSWER)edge dislocation
Distinct region within the materials structure where the atoms or ions are arranged in a regular and
repeating crystal lattice pattern - (ANSWER)grain
interfaces between adjacent grains with different orientations of their crystal lattice - (ANSWER)grain
boundaries
Disadvantages of surface defects - (ANSWER)1. decrease elctrical and thermal conductivity
2. increase corrosion
The crystal returns to original shape when force is removed - (ANSWER)elastic
A permanent change occurs when the force is greater than the electrostatic force holding the atoms in
their lattice positions - (ANSWER)plastic
