2. Atomic Bonds Flashcards
FLOWCHART: Sub-atomic structure defines _____, which defines ____ and ____.
Atomic bonds, which defines basic mat properties as well as material types.
Atomic packing is modified by ____
Packing defects
What two things define microstructure?
Atomic packing and packing defects.
Materials Processing techniques controls what two things?
Packing defects and macroscopic defects
What gives “actual material properties”
atomic packing and packing defects, modded by macroscopic defects.
What defines ideal material properties?
Microstructure does.
What are two ways to control atomic defects and macroscopic defects?
Materials processing techniques, as well as component production techniques (i.e. machining can improve surface finish)
What are the ICME scales?
name five
Electronic Nano Micro (microstructure) Meso (microstructure) Macro
BONDING
What is a material?
A group of atoms, bonded together, used as a material
Why do atoms group together?
Atoms group together to minimize energy.
What is the ground state?
The lowest energy state of ONE atom
When is ground state achieved?
when the outermost shell is filled
What is a stable electron configuration?
Outermost shells are filled. i.e. noble gases.
What do you call an atom with a slight excess of electrons?
Metallic or electropositive.
What do you call an atom with a slight deficiency of electrons
Nonmetallic or electronegative.
Compare and contrast ground state and stable electron configuration.
They both describe the lowest energy state. Ground state is for ONE atom, S.E.C. is for a GROUP of atoms.
How does the ground state and stable electron configuration differ for noble gases
for noble gases they are the same.
HOW DO ATOMS BOND
By coulombic forces
What are coulombic forces?
Forces created between charged particles: repulsive if they’re charged the same way
How are these coulombic forces created?
By creating a stable electron configuration
How does ionic bonding happen?
Metal gives an electron to the non-metal. Coulombic forces keep the two ions attracted.
Is ionic bonding directional?
No - forces are always attractive
Metals, polymers, ceramics: which one performs ionic bonding?
Ceramics!
Up/down and left/right: which directions increase electronegativity?
UP, RIGHT increasing EN.
Electropositive: excess of electrons
