Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
What does Amorphous mean? |
means that they have the same strong atomic bonds present in crystalline materials, but have only short-range order, much like liquid. |
|
What is a ceramic? |
Is a material that is bonded with ionic bonds. |
|
What are colloids? |
are a two phase material. They are mixtures of gases, liquids, or solids at a microscopic level. |
|
What are composites? |
are materials that are made up of two are more materials. |
|
What are covalent bonds? |
are the result of two atoms sharing a pair of electrons. |
|
What is cross-linking? |
The linking of one coil (or polymer chain) across to another with wire (or a covalent bond). |
|
Define a crystalline? |
are solids that have a consistent spatial relationship of atoms or molecules repeated hundreds to thousands to millions of times. |
|
What are dental materials? |
a subgroup of materials science. Is part of a larger field of biomaterials. |
|
What are emulsions? |
are a type of colloid composed of two liquids that do not blend together to form one liquid. |
|
What is a fluctuating dipole? |
Noble gases such as helium. Have a symmetrical charge distribution. Liquifies when cool. Have unequal distribution of electrons for short periods of time. |
|
What are hydrogen bonds? |
A special case of permanent dipoles. the electron spends most of its time with the oxygen making a polar molecule. |
|
What are ionic bonds? |
Are the result of an electron being given up by one atom and being accepted by another. |
|
What is long-range order? |
Are molecules that are repeated hundreds of thousands to millions of times |
|
What is materials science? |
Is the part of the physical sciences that seeks to explain the properties and performance of materials by examining their internal structure. |
|
What are metallic bonds? |
are similar to covalent bonds in that valence electrons are shared between atoms. The difference is that the electrons in a metal object are not shared by two atoms but shared by all the atoms that make up the object. |
|
Define metals. |
Are typically dense, heavy materials. they are good conductors of both electricity and heat and are cold at room temperature. |
|
What are permanent dipoles? |
Is when one atom involved in the bond is partially positive, and the other is partially negative. They are weak bonds. |
|
What are polymers? |
Are composed of long chains of covalently bonded, repeating units. |
|
What are primary bonds? |
Are the strong bonds between atoms that involve the transfer or sharing of electrons between atoms. |
|
What are secondary bonds? |
Also known as van der Waals forces, are the result of partial charges from an uneven distribution of electrons around an atom or a molecule. The partial charges can be either weak or strong and temporary or permanent. |
|
What is short-range order? |
Is a consistent spatial relationship among atoms or molecules 5 to 10 neighbors apart. |
|
What are valence electrons? |
The electrons in the outer shell of atoms that are involved in chemical reactions and atomic bonding. |
|
Name three phases of atomic bonding. |
Gases Liquid Solids |
|
Name three types of primary bonds. |
Ionic Covalent Metallic |
|
Name three types of secondary bonds. |
Permanent dipoles Hydrogen dipoles Fluctuating dipoles |
|
Name five types of dental materials and their atomic bonds. |
Ceramics - Ionic Polymers - Covalent Metals - Electron cloud Composites - Combination Colloids - suspension |
|
Pure gold is _____ carat. |
24 carats |
|
The molecules found in a pane of glass can be best described as: |
Amorphous solid, having short-range order. |
|
A partial charge resulting from an uneven distribution of electrons around an atom forms a bond known as: |
Secondary bond |
|
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 a "positive cores" in a "cloud of negative mobile valence electrons"? |
Metallic bonds |
|
A notable advantage of using ceramic materials in dentistry in the property of: |
Translucency |
|
A dental polymer with many cross-lings as compared to one with no cross-links would be a dental material that is: |
Stiff and strong |
|
All of the following are examples of a composite except: A. set jello with sliced peaches B. Enamel C. Fiberglass D. Tin foil |
D. Tin foil |
|
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. |
Permanent dipole |
|
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 |
|
A mixture of two liquids that do not blend together to form one liquid is termed a (an): |
Emulsion |
|
When two atoms share a pair of electrons, the resulting atomic bond is termed a (an) _________ bond. |
Covalent |