Dental Materials Ch. 2

Question 1

the molecules found in a pane of glass can be best described as

(a) Crystalline solid, having short-range order only

(b) Crystalline solid, having both short-range and long-
range order

(c) Amorphous solid, having long-range order
(d) Amorphous solid, having short-range order

Answer 1

(d) Amorphous solid, having short-range order

Question 2

a partial charge resulting from an uneven distribution of electrons around an atom forms a bond known as

(a) Metallic
(b) Secondary
(c) Covalent
(d) Ionic

Answer 2

(b) Secondary - partial charges result

Question 3

what type of bond is formed when the electrons are shared by all the atoms that make up that object and may be thought of as positive cores in a cloud of negative mobile valence electrons

(a) Metallic
(b) Secondary
(c) Covalent
(d) Ionic

Answer 3

(a) Metallic

Question 4

a notable advantage of using ceramic materials in dentistry is the property of

(a) Transparency
(b) Translucency
(c) Opacity
(d) Brittleness

Answer 4

(b) Translucency

Question 5

a dental polymer with many cross-links as compared to one with no cross-links would be a dental material that is

(a) Flexible but strong
(b) Flexible and weak
(c) Stiff and strong
(d) Stiff but weak

Answer 5

(c) Stiff and strong

Question 6

all of the following are examples of composite except

(a) Set Jell-O with sliced peaches
(b) Enamel
(c) Fiberglass
(d) Tin foil

Answer 6

(d) Tin foil

Question 7

when the shared electrons of a covalent bond are not shared equally, and one of the bonded atoms is partially positive and the other is partially negative a ________ is formed

(a) Permanent dipole
(b) Fluctuating dipole
(c) Hydrogen bond
(d) Primary bond

Answer 7

(a) Permanent dipole

Question 8

the sliding of atoms past each other allows this material to bend, not fracture, and maintain its strength. this material is an example of

(a) Metal
(b) Ceramic
(c) Polymer

Answer 8

(a) Metal

Question 9

a mixture of 2 liquids that do not blend together to form 1 liquid is termed a

(a) Composite
(b) Emulsion
(c) Colloid
(d) Solution

Answer 9

(b) Emulsion

Question 10

when 2 atoms share a pair of electrons, the resulting atomic bond is termed a ________ bond

(a) Secondary
(b) Ionic
(c) Covalent
(d) Metallic

Answer 10

(c) Covalent