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Materials- Midterm > Structure of Matter > Flashcards

Structure of Matter Flashcards

1
Q

The Atom is composed of what 2 things?

A

nucleus (proton + neutron) and electrons

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2
Q

Atomic Orbitals

A
  • refers to the probability in space (S,P, D; D= higher energy)
  • hybridized (sp3/ sp2)
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3
Q

What are the ratios of electrons to protons in:

1) elemental state
2) cationic state
3) anionic state

A

1) e- = p+

2) e- p+ (negative charge)

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4
Q

The atomic number refers to what?

A

number of protons

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5
Q

Atomic weight/ avogadro’s number

A

AW= weight of 1 mol of atoms; AN= 6x10^23 atoms

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6
Q

What are the 4 primary phases? Rank into highest energy

A

(highest) plasma > gas > liquid > solid (lowest)

Higher temperature More vibrational energy less association of atoms less association of atomic particles

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7
Q

1) _______: carbon, hydrogen, O2, N2, phosphorous
2) ______: silicon, Oxygen (SiO2), oxides of metals
3) ______: transition elements

A

1) primary polymer elements
2) primary ceramic elements
3) primary metallic elements

NOTE: Polymers are gernally carbon based

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8
Q

Basic components of cermics is _____

A

Silica (silicon + Si02 + oxides of metals)

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9
Q

There are primary bonds and secondary bonds. Which one is stronger?

A

primary

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10
Q

ionic, covalent and metallic are examples of what type of bonds?

A

primary bonds

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11
Q

What primary bond is the backbone bond in polymers?

A

covalent bonds

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12
Q

Hydrogen, Polar and Van der Waals forces are examples of what type of bonds?

A

secondary bonds

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13
Q

_________ are the probability of space produced when the atomic orbitals of neighboring atoms combine in a covalent bond.

A

Molecular Orbitals

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14
Q

For molecular orbitals, there are sigma-antibonding and sigma-bonding. Which of the two has higher energy?

A

sigma-antibonding

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15
Q

What are 3 characteristics of bonds?

A
  • bond length
  • bond angle (depends on hybridization of orbitals- helps establish lattice structure)
  • number of bonds (coordination number/ number of nearest neighbors)
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16
Q

As you push atoms closer to each other, there etiher attractive or repulsive forces (i.e. protons vs protons). In a force graph, the graph equals ______ when summing attraction and repelling forces are equal

A

zero (O)

NOTE- The bond is equivalent to when attractive/ repulsive forces equal

17
Q

A ________ are ways of describes solids structures in a 3D space. What are its 2 components?

A

Bravais Lattice Structure

Cartesian Coordinates + Mathematical Derivation

18
Q

How many Bravais Lattice structures are there? Which one is the strongest structure?

A

14

IDK the second question???????

19
Q

In a Bravais Lattice, if all 3 lengths/ angles (a,b,c) are the same and equal 90 degress, what shape is it?

A

a cube (simplest mathmatical description of a bravais structure)

20
Q

What are 2 ways you determine a lattice structure?

A
  • Xray diffraction pattern

- Miller indices (atom points/ directions)

21
Q

What are the 2 closest ways for packing?

A
  • Hexagonal Close Pack (HCP)

- Face Centered Cubic (ccp)

22
Q

What are the ratio of atoms per lattice point for:

1) most metals
2) most ceramics/ diamons

A

1) single atom (simple)

2) multiple atoms per lattice point

23
Q

______ refers to several different relationships with molecules to adopt a different lattice strcutrues (i.e. carbon, iron or SiC).

A

polymorphism

24
Q

Which of the following are amorphous or crystalline?

  • liquid
  • solid
  • gas
A

liquid/ gas= amorphous

solid= crystalline

25
Q

T/F: Glass is an amorphous structure even though it is a solid.

A

True

26
Q

Define the units of length:

1) millimieter= ?
2) micrometer (micron)= ?
3) nanometer= ?
4) angstrom= ?
5) picometer= ?

A

1) Millimeter = 10-3 meters
2) Micrometer (Micron)= 10-6 meters
3) Nanometer = 10-9 meters
4) Angstrom = 10-10 meters (order of atomic bonds
5) Picometer = 10-12 meters

27
Q

If 100 microns and preparation is 1 mm wide, how many sections can you fit?

A

10

28
Q

There are imperfections in structures; what are they? (4)

A
  • point defects
  • line defects
  • surfaces/ boundaries
  • impurities
29
Q

What is the exception to imperfections in structures?

A

whiskers- near perfect crystals

30
Q

Examples of point defects:

1) _______: an atom is missing from the structure
2) _______: oppositely charged ions leave their lattice sites, creating vacancies
3) _______: two or more atoms may share one lattice site, thereby increasing its total energy
4) _______: an atom or ion occupies a normally vacant site other than its own

A

vacancy
schottky defect,
intersticialcy
frenkel defect

31
Q

Examples of line defects:

1) _______: an extra half-plane of atoms is introduced mid way through the crystal, distorting nearby planes of atoms
2) ______: efect line movement is perpendicular to direction of the stress and the atom displacement, rather than parallel

A

edge dislocation

screw dislocation

32
Q

______ is a gathering of atomic lattice structures with disorder at the boundaries between them. What are 3 characteristics of them?

A

Grain Structure

  • less organized
  • higher energy
  • form upon cooling from a liquid to solid state (nucleation and grain growth)
33
Q

Impurities: If copper atoms is randoml distributed in gold solution, then it’s a _______. If copper atoms take ordered positions, it is an ________.

A

solid solution; intermettalic compound

34
Q

Which is strong: a solid solution or an intermettalic compound?

A

IC

35
Q

There are imperfections in structures; what are they? (4)

A
  • point defects
  • line defects
  • surfaces/ boundaries
  • impurities
36
Q

Rate the following in terms of diffusion rates: liquid, gas, solid

A

fastest: gas > liquid > solid

37
Q

______ refers to structural changes with temperature, which occurs in polymeric materials (i.e if you drink coffe, it softens your composite slighly)

A

Glass Transition Temperature

38
Q

T/F: , if volume changes, then it states will (i.e. coulb be a crytalline then to a rubbery state)

A

True

39
Q

1) _______: rates of change; how long it takes for states to change (rate reactions take place)
2) _______: equilibrium states; Lower energy state is what compounds want to exist at. Rate and
determines by Delt(g)

A

1) Kinetics

2) Thermodynamics

Materials- Midterm (2 decks)

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