Lecture 1 Flashcards
what promotes bonding?
what types of bonds are there?
what properties are inferred from bonding?
what is the atomic number Z?
protons/neutrons
are electron energy states continuous?
no, they have discrete energy states (so levels)
what is the quantum-mechanical principle
electrons have discrete energy states
what energy level do electrons tend to occupy
the lowest available energy state
(picture of energy states– need to do)- electron energy states
when you form bonds, what electrons are important?
the lower ones are not, they are protected by the outer ones. the outer ones are more loosly bonds and they create bonds and can be moved
what are valence electrons
electrons in the outermost shell (the number)
what shells are the most stable
filled shells
what electrons are the most available for bonding
valence electrons– they try to make bonds and interact
are most elements stable?
no
what is the pauli exclusion principle
there can’t be two electrons in the same energy state (w same spins)
what to remember when identifying the valence electrons in
d is “higher” than s
what properties do valence electrons determine?
chemical
electrical
themal
optical
what side of the periodic table has electropositive elements
left (give up electrons)
what side of the periodic table has electronegative elements
right (want electrons)
are nonmetals on the right or left of the table
right
what does a large electronegativity value suggest
large tendency to acquire electrons
what is the highest value for electroneg
4.0 (on the right)
what is the lowest value for electroneg
0.7 Fr
what are the four primary bonds
ionic, covalent, mixed, and metallic
what are secondary bonds
van der waals
what does ionic bonding occur between
positive and negative ions (two elements with very different electronegativity)
what does ionic bonding require
electron transfer
*and large dif in electroneg
what do the metals and nonmetals do in ionic bonding
metals donate e
nonmetals accept e
when you form any system, what does it mean in terms of energy?
it always takes the lowest possible energy state
(picutre of the attraction thign for ionic bonding)
what does the bottom point show on the graph?
repulsive energy stays at the top because it’s always positive
the minimum of the curve responds to the steady state?
what kind of energy does attractive have between charges
negative because it’s potential, coulomb force
what’s the equation associated with energy attractive and repulsive
picture
what kind of bonding happens in ceramics?
ionic
what kind of elements covalent bond
ones with similar electroneg, they share the electrons
what orbitals dominate bonding in covalent bonding?
s and p
explain how methane covalent bonds?
add pic
what is mixed bonding?
ionic-covalent mixed bonding
what is an important measurement when looking at mixed bonding
% ionic character
what are X sub A and X sub B
pauling electronegativities
how does metallic bonding work
a delocalized electron cloud (sea of electrons)
(slides on van der waals)
slides from summary slide
describe the energy and direction of ionic bonding
large bond energy and directional bonding energy
what is the coefficient of thermal expansion of a material?
pictures of formulas
