LECTURE 1 (ME PREP) Flashcards
(30 cards)
A special group of polymers in which molecular chains are entangled but not interconnected. They can be easily melted and formed into useful shapes.
THERMOPLASTICS
An environmental effect which dramatically alters the properties of material. Metals and alloys that have been strengthened by certain heat treatments or forming techniques may suddenly lose their strength when heated.
Temperature
A given element has an atomic number of 12. All of the following statements are correct, EXCEPT:
a. it is a metal
b. it has 3 electron shells
c. it has 2 protons
d. its atomic mass is 24 amu
it has 2 protons
On the periodic chart, elements in the same vertical column have the same ____.
Select one:
a. degree of attraction between the nucelus and the outermost electrons
b. number of occupied energy levels
c. ionization energies
d. configuration of electrons in the outermost energy level
configuration of electrons in the outermost energy level
It is described as the region in space with a specific shape where a pair of electrons is most likely to be found.
orbital
The term __________ means the chemical make-up of a material.
composition
It is found out that the maximum number of electrons in each energy level is equal to 2(n) squared. Therefore, in the 4th energy level there are ___ electrons.
32
A pair of electrons that is shared between two atoms is a/an ____.
covalent bond
What is the principal assumption that is made in the build-up of electronic structures of atoms?
The orbitals calculated for hydrogen can be used for all the rest of the atoms.
How many 3d orbitals are there?
5
Properties of a material, such as strength, that describe how well a material withstands applied forces, including tensile or compressive forces, impact forces, cyclical orf fatigue forces, or forces at high temperatures.
Mechanical properties
The term ___________ means how materials are shaped into useful components to cause changes in the properties of different materials.
processing
A special group of polymers that decompose rather than melt upon heating. They are normally quite brittle due to a relatively rigid, three-dimensional network structure.
Thermosets
These materials are a group of new and state-of-the-art materials now being developed that will have a significant influence on many of our technologies
Smart materials
When high energy ultraviolet light (UV light) falling on a metal surface causes electrons to be ejected, as the intensity of the light is increased
the kinetic energy of the ejected electrons increases
The term _________ refers to how materials are made from naturally occurring or other chemicals.
synthesis
A diagram showing how performance-to-cost ratio of materials depend upon th composition, microstructure, synthesis and processing.
Materials Science and Engineering Tetrahedron
The nucleus accounts for the mass of an atom and is positive. Which statement explains this property of the nucleus?
It is made up of protons and neutrons
Characteristics such as color, elasticity, electrical or thermal conductivity, magnetism, and optical behavior that generally are not significantly influenced by forces acting on a material.
Physical properties
These materials are typically very hard but extremely brittle (lack ductility), and are highly susceptible to fracture.These materials are typically insulative to the passage of heat and electricity and are more resistant to high temperatures and harsh environments.
Ceramics
It is an interdisciplinary field of that studies and manipulates the composition and structure of materials across length scales to control materials properties through synthesis and processing.
Materials Science and Engineering
Metals and ceramics may disintegrate and polymers and non-oxide ceramics may oxidize. Materials are attacked with strong liquids which may lead to permanent failure. What environmental effect is described.
Corrosion
A material composed of two or more individual materials with a design goal to achieve a combination of properties that is not displayed by any single material, and also to incorporate the best characteristics of each of the component materials.
Composites
Which of the following kinds of bonds are the strongest?
a. covalent
b. permanent dipole-dipole interactions
c. induced dipole-dipole interactions
d. hydrogen bonds
COVALENT
