Chapter 9 Flashcards
What are electron domains?
Regions where electrons are most likely to be found
How many electron domains does multiple bonds count as?
one
How do you determine the electron domain-geometry?
count the total number of bonding and nonbonding electron domains
What is the electron-domain geometry when there is 2 domains?
Linear
What is the electron-domain geometry when there is 3 domains?
Trigonal Planar
What is the electron-domain geometry when there is 4 domains?
Tetrahedral
What is the electron domain geometry when there is 5 domains?
Trigonal Bipyramidal
What is the electron domain geometry when there is 6 domains?
Octahedral
What is the first step in determining molecular shapes?
draw the lewis structure
What is the second step in determining molecular shape?
determine the electron-domain geometry
What is the third step in determining molecular shape?
Use the arrangement of the bonded atoms to determine the molecular geometry
How do you find molecular geometry?
counting only bonding electrons domains
What is the molecular geometry of a tetrahedral if there is two nonbonding pairs?
bent
When there is the same amount of bonding and nonbonding domains what is the molecular geometry?
there are the same
What is the molecular geometry of a tetrahedral if there is only one nonbonding pair?
Trigonal pyramidal,
Which is larger a bonding or a nonbonding pair?
nonbonding are larger
Which repulsions is larger bonding or a nonbonding pairs?
bonding repulsions
Which have larger electron domains single or multiple bonds?
multiple bonds
How to find the electron domain geometry when there is multiple atoms in the middle?
consider the geometry of each middle atom
Which elements can have more than four bonds?
period 3 and 6
What are the four molecular geometries for a trigonal bipyramidal?
Trigonal bipyramidal
* Seesaw
* T-shaped
- Linear
What is the molecular geometry for a trigonal bipyramidal when there is one nonbonding pair?
seesaw
what is the molecular geometry for a trigonal bipyramidal when there is two nonbonding pairs?
T-Shaped
What is the molecular geometry for a trigonal bipyramidal when there is a three nonbonding pairs?
Linear
What are the three molecular geometries for a Octahederal electron domain?
- Octahedral
- Square pyramidal
- Square planar
What is the molecular geometry for a octahederal when there is one nonbonding pairs?
square pyramdial
what is the molecular geometry for a octahederal when there is two nonbonding pairs?
square planar
When is a dipole polar?
bond dipoles are not symmetrical
When is a dipole nonpolar?
bond dipoles cancel/equal or arranged symmetrical around the center
How do you assign a dipole moment?
based on the electronegativity
How do you determine the direction of the dipole moment?
towards the most electronegative
What is valence electron bond theory?
electrons of two atoms occupy the same space
How are hybrid orbitals formed?
“mixing” valence-bond theory atomic
orbitals to create new orbitals of equal energy
What are hybrid orbitals called?
degenerate orbitals
What is the process of mixing valence bond theory atomic orbitals called?
hybridization
What is the hybridization of a linear shaped molecule?
sp
What is the hybridization of a trigonal planar shaped molecule?
sp2
What is the hybridization of a tetrahederal shaped molecule?
sp3
When AB2 is Linear is it nonpolar or polar?
Nonpolar
When AB2 is bent is nonpolar or polar?
Polar
When AB3 is Trigonal planar nonpolar or polar?
Nonpolar
When AB3 is Trigonal pyramidal or T-shaped is it polar or nonpolar?
Polar
When AB4 is Tetrahedral or square planar polar or nonpolar?
nonpolar
When AB4 is seesaw- shaped polar or nonpolar?
Polar
When AB5 is trigonal bipyramidal is it nonpolar or polar?
Nonpolar
When AB5 is square pyramidal is it nonpolar or polar?
Polar
When AB6 is octahedral is polar or nonpolar?
Nonpolar
What is a pi bond?
the overlap regions lie above and below the internuclear axis.
Which bond is stronger a pi bond or a sigma bond?
sigmabond
What is sigma bond?
the line joining the two nuclei passes through the middle of the overlap region
When two s orbitals overlap in a H2 molecule is it a sigma bond or a pi bond?
Sigma bond
When there is an overlap in the H s orbital and a Cl p orbital in HCl is it a sigma or pi bond?
sigma bond
When there is an overlap of two p orbitals one from each Cl in Cl2 is it a sigma or pi bond?
sigma bond
When there is an overlap of an F p orbital and a Be sp hybrid orbital in BeF2 is it a pi bond or sigma bond?
sigma bond
When there is an overlap of a H s orbital and a N sp3 hybrid orbital in NH3 is it sigma bond or a pi bond?
sigma bond
Is a single bond a sigma bond or a pi bond?
sigma bond
Is a double bond a sigma or pi bond?
one sigma and one pi bond
what are delocalized electrons?
electrons that are spread over a number of atoms in a molecule
What is a molecular-orbital theory?
A theory that accounts for the allowed states for electrons in molecules by using specific wave functions
What is a bonding molecular orbital?
a molecular orbital in which the electron density is concentrated int eh internuclear region.
How is the second MO formed?
Destructive combination
What is destructive combination?
combining the two atomic orbitals in a way that causes the electron density to be canceled in the central region where the two overlap
What is antibonding molecular orbital?
a molecular orbital in which electron density is concentrated outside the region between the two nuclei of bonded atoms
What is a nodal plane?
a plane where the electron density in an atom or a molecule is zero
What is a energy-level diagram?
A diagram that shows the energies of molecular orbitals relative to the atomic orbitals
What is a bond order?
half the difference between the number of bonding electrons and the number of anti-bonding electrons
How do you find bond order?
1/2(number of bonding electrons-number of anti-bonding electrons)
When there is a Resonance structure does it have localized or delocalized electrons?
delocalized pi bonds number of resonance strucutre.
What does the number of MOs formed equal in period 2 atoms?
number of atomic orbitals
What can each MO accommodate?
at most two electrons with their spins paried
What is two atomic orbitals proportional to?
their overlap
What happens when MOs of the same energy are populated?
one electron enters each orbital before spin pairing
What is a pi molecular orbitals?
overlap sideways an thus concentrate electron density above and below internuclear axis
What is paramagnetism?
a property that substance possesses if it contains one or more unpaired electrons
What is a diamagnetism?
a type of magnetism that causes a substance with no unpaired electrons
What is the bond angle for NH3?
107
What is the bond angle for H2O(bent)?
104.5
What is the bond angle for the H-C- bond in CH3CN?(Tetrahedral)
109.5
What is the bond angle for the C-C(—)N bond in CH3CN(Linear)?
180
When is a molecule planar?
When all atoms are in the same plane
When bond length decrease what does the energy do?
increase
When bond order increases what does bond length due?
decreases
When bond order increases what does stability due?
increase
How do you find bond order?
Number of electrons bonded-Number of electrons nonbonded/2
When the bond order is zero does the molecule exist?
No
