MSE Note Test1.pdf - Chapter 1 • Properties of solid...

Chapter 1
• Properties of solid materials may be grouped into six different categories: mechanical, electrical,
thermal, magnetic, optical, and deteriorative.
1.4 Classification of Materials
• Solid materials have been grouped into three basic categories:
o Metals:
▪ Atoms are arranged in a very orderly manner.
▪ Relatively dense in comparison to the ceramics and polymers.
▪ Relatively stiff and strong.
▪ Ductile (i.e., capable of large amounts of deformation without fracture), and are
resistant to fracture.
▪ Have large numbers of nonlocalized electrons.
o Ceramics:
▪ Compounds between metallic and nonmetallic elements.
▪ Relatively stiff and strong.
▪ Extreme brittleness (lack of ductility) and are highly susceptible to fracture.
▪ Insulative to the and are more resistant to high temperatures and harsh
environments.
o Polymers:
▪ Organic compounds that are chemically based on carbon, hydrogen, and other
nonmetallic elements.
▪ Very large molecular structures.
▪ They are not as stiff or strong.
▪ Extremely ductile and pliable.
▪ Tendency to soften and/or decompose at modest temperatures.
▪ Low electrical conductivities.
o Composites:
▪ Composed of two (or more) individual materials that come from the categories
previously discussed.
Chapter 2
2.2 Fundamental Concepts
• Atomic Number: number of protons in the nucleus.
• Atomic Mass: sum of the masses of protons and neutrons within the nucleus.
• Isotopes: atoms of elements with two or more different atomic masses.
• Atomic Weight: weighted average of the atomic masses of the atom’s naturally occurring
isotopes.
• In one mole of a substance, there are 6.022 x 10^- 23 (Avogadro’s number) atoms or molecules.
2.3 Electrons in Atoms
• Quantum Numbers:
o The four electron quantum numbers are:
▪ n: electron orbital size (average distance from the nucleus)

▪ l: orbital shape.
• Range of values: l = 0 to l = (n 1)
▪ ml: number of electron orbitals
• can take on integer values between -l and +l
▪ ms: spin moment (must be oriented either up or down).
• Two values are possible: +1/2 (for spin up) and -1/2 (for spin down).
• Electron Configurations:
o Electron states: values of energy that are permitted for electrons
o Pauli exclusion principle: each electron state can hold no more than two electrons that
must have opposite spins.
o Electron Configuration: way these states are occupied.

• Atomic Models:
o Bohr Atomic Model: early attempt to describe electrons in atoms, in terms of both
position (electron orbitals) and energy (quantized energy levels).
▪ Electrons are assumed to revolve around the atomic nucleus in discrete orbitals.
▪ The position of any electron is defined in terms of its orbital.
▪ Energies of electrons are quantized
o Wave-Mechanical Model:
▪ Electron is considered to exhibit both wavelike and particle-like characteristics.