solids Flashcards
What are allotropes?
Different molecular structures of the same element
What are metallic bonds?
High electron mass in metals resulting in a “sea” of electrons
What are crystalline solids?
Solids with an ordered array of molecules
What is the difference between square and close packing?
Square = grid arranged molecules
Close = zig-zag arranged molecules
How are molecules arranged in a simple cubic cell (scc)?
one molecule in each corner
How many molecules are in one scc?
one
What is the edge length of an scc?
2r
What is the packing efficiency of an scc?
52%
How are molecules arranged in a body-centered cubic cell (bcc)?
One molecule in the middle, and one in each corner
How many molecules are in one bcc?
two
What is the edge length of a bcc
4r/√3
What is the packing efficiency of a bcc?
68%
How are molecules arranged in a face-centered cubic cell (fcc)?
one molecule on each face, and one in each corner
How many molecules are in a fcc?
four
What is the edge length of a fcc?
4r/√2
What is the packing efficiency of a fcc?
74%
What is an alloy?
A blend of metals
What are holes?
Gaps within lattice poi
What is a superconductor?
A material with no resistance to electrical flow
What is a critical temperature (Tc)?
Temperature when a material becomes a superconductor
What is x-ray diffraction?
A lab technique used to determine arrangement of atoms in a lattice
