Engineering Materials Ch 2

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Engineering Materials Ch 2
2013-02-17 20:49:20
EGRT 1305

Chapter 2 Test Review
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  1. Scientific methods and inquiry are based on:
    a. Recognizing patterns in the behaviors of different substances.

    b. Developing a model that explains these observations.

    c. The model shoud be able to be used to predict the behavior of other substances.

    d. When possible the model should be quantitative.

    e. Models should make predictions that can be tested experimentally.
  2. Early "scientist" thought all matter was composed of:
    earth, air, fire and water
  3.             was the first person to conceive of the idea of the atom.
  4. The              was the first subatomic particle discovered.
  5.             was the first modern scientist to propose the existence of the atom. In his theory, the atom mist resemble a           ball.
    Dalton, billiard
  6. Earnest Rutherford was shocked to discover that the atom is 99% empty             . His theory proposed the idea of a               where most of the mass and positive charge would reside.
    space, nucleus
  7. Neils Bohr proposed that;
    a. Electrons could only orbit the nucleus at a fixed distance, its distance from the nucleus (i.e. their radii) being proportional to its energy.

    • b. Only orbits with certain energies were allowed, in other words, charge is quantative.
    • c. The energy the electron in a given orbit is proportional to it's distance from the nucleus.

    • d. Light is absorbed when an electron moves to a higher energy orbit.
    • e. Light is  emitted  when an electron falls to a lower energy orbit.
  8. The modern view of the atom is that in the center is a           made up of         and       . All of which is surrounded by electrons of different        strengths.
    nucleus, protons, neutrons, energy
  9. Each atom can be uniquely described by four            numbers.
  10. The periodic table groups elements by common              
  11. Matter can be divided into 3 general categories:
    a. Elements substances that contain only 1 kind of atom.

    b. Compounds substances that contain more than one element combined in fixed proportions.

    c. Mixtures are mechanically created, not chemically  They can have different compositions from sample to sample.
  12. Dmitry Mendeleev is credited with the invention of the                       .
    periodic table
  13. The               is the smallest particle that can be used to identify an element.
  14. The                     is the smallest particle that can be used to identify a compound.
  15. The atomic number represents the number of                 in the nucleus of the atom.
  16. An        is an atom with a positive or negative charge.
  17. More than 50 of the known elements are metals. Some of the distinguishing characteristics of metals are:
    a. strength

    b. Good electrical conductivity

    c. Good thermal conductivity

    d. Luster

    e. The ability to be deformed permanently to a fair degree without fracturing

    f. Relatively high specific gravity
  18. In general, the behavior of metal crystals depends on:
    a. The lattice type

    b. The inter-atomic forces

    c. The spacing between planes of atoms

    • d. The density of atoms on various planes
  19. In covalent bonding, stable electron configurations are achieved by                   electrons between adjacent atoms.
  20. In Ionic bonding, one atom gives up an            to another atom
  21. In                     bonding, valence electrons are not bound to any particular atom but allowed to more or less drift free throughout the entire metal.
  22.                          are weak attractive forces between molecules with oppositely charged dipoles.
    Van der Waals forces
  23. The four types of atomic bonding forces are:
    a. ionic

    b. covalent

    c. metallic

    d. Van der Waals
  24. In crystalline materials, atoms are situated in repeating or periodic              over long range atomic distances.
  25. Metals with the structure below are called?
    Body Centered Cubic
  26. The coordination number for BCC is?
  27. Metals with the structure below are called?
    Face Centered Cubic
  28. The coordination number for FCC metals is?
  29. Metals with the structure below are called?
    Hexagonal Close Packed
  30. The coordination number for HCP metals is?
  31. Metals that can have more than one crystalline structure are called?
  32.                  is a crystal imperfection characterized by regions of severe atomic misfit where atoms are not properly aligned and surrounded by neighboring atoms.
  33. Dislocations in crystalline lattices come from:
    a. crystal mismatch during solidification

    b. external stresses

    c. phase transformations

    d. atomic mismatch effects from alloying elements
  34. Why are dislocations in metals important?
    They are the primary means by which metals deform and are strengthened