Units 9 And 10 Flashcards
2 electrons = electron pair geometry of
Linear
3 electrons = electron pair geometry of
Trigonal planar
4 electrons = electron pair geometry of
Tetrahedral
5 electrons = electron pair geometry of
Trigonal bipyramidal
6 electrons = electron pair geometry of
Octahedral
Linear
2 electrons = electron pair geometry of
Trigonal planar
3 electrons = electron pair geometry of
Tetrahedral
4 electrons = electron pair geometry of
Trigonal bipyramidal
5 electrons = electron pair geometry of
Octahedral
6 electrons = electron pair geometry of
Linear with no lone pairs molecular geometry
Linear
Trigonal planar with no lone pairs
Trigonal planar
Trigonal planar with 1 lone pairs
Bent
Tetrahedral with no lone pairs
Tetrahedral
Tetrahedral with one lone pair
Trigonal pyramidal
Tetrahedral with 2 lone pairs
Bent
Trigonal bipyramidal with 1 lone pair
See-saw
Trigonal bipyrmidal with 2 lone pairs
T shaped
Trigonal bipyramidal with 3 lone pairs
Linear
Octahedral with no lone pairs
Octahedral
Octahedral with 1 lone pair
Square pyramidal
Octahedral with 2 lone pairs
Square planar
Octahedral with 3 lone pairs
T shaped
Octahedral with 4 lone pairs
Iinear
Transfer one or more electrons from one to another to form ions
Ionic
Electrons are shared between atoms
Covalent
Energy change occurring when separated ions are packed together to form a crystalline solid
Lattice energy
Based on Coulomb’s law, which of the following is predicted to have a larger lattice energy?
LiF
Does MgO have a larger Latrice than NaCl?
Yes
Molecule formed by covalent bonds
Covalent compound
A 2D representation of bonding and non bonding electrons a molecule or polyatomic ion
Lewis structure
An electron pair found in the space between atoms
Bonding pair
An electron pair localized on a given atom
Lone pair
Valence electrons equal
Group Number
A condition occurring when a Lewis structure can be drawn for a particular ion
Resonance
Has fewer than 8 electrons
BF3
Has more than 8 electrons
SF6
Formal charge
Group # - (# lp + 1/2 bonding)
The best Lewis structure is the
One that minimizes formal charge
The octet rule usually occurs with
Boron and elements of higher periods (3 and up)
Linear geometry angle
180
Example of linear geometry
BeF2
Example of trigonal planar
BF3
Trigonal planar angle
120
Tetrahedral example
CF4
Tetrahedral angle
109.5
Trigonal bipyramidal example
PF5
Trigonal bipyramidal angle
120 and 90
Octahedral example
SF6
Octahedral angle
90
H2O is
Bent
Repulsive forces decrease in the following order
Lp vs lp greater then lp vs bonding greater than bonding vs bonding
Electrons are not shared equally, one atom attracts them more strongly than the other
Polar covalent bond
Electrons shared equally
No polar covalent bond
Example for ionic bond
NaCl
Example for covalent bond
HCl
Example for no polar covalent bond
Cl2
Ionic character of bond decreases from (blank) to (blank)
Ionic to nonpolar
The tendency of an atom in a molecule to attract density to itself
Electronegativity
Who came up with electronegativity
Linus Pauling
The greater the electronegativity difference between 2 atoms in a bond, the (blank) the polarity
Greater
Which element has the highest electronegativity
F 4.0
Covalent usually has a electronegativity difference of
0-0.3
Polar covalent usually has a electronegativity difference of
0.4-2.0
Ionic usually has a electronegativity difference of
2.1-4
of bonds between atoms
Bond order
Distance between the nuclei of two bonded atoms
Bond length
1 pair of electrons shared = bond order of
Single: 1
2 pair of electrons shared = bond order of
Double: 2
3 pairs of electrons shared = bond order of
Triple: 3
Energy required to break a chemical bond
Bond energy
Bond enthalpies are always
Positive
Energy of reaction equation
Sum of bond energy of bonds broken - sum of bond energy of bonds formed
Based on their Lewis structure which molecule has the longest carbon oxygen bond? Carbon dioxide and carbon monoxide
Carbon dioxide
Order bond number from shorter to longest bond
Triple, double, single
Bond length (blank) as the # of shared electrons increases
Shortens
Single bond has the (blank) bond length
Longest
Double bond has the (blank) bond length
Middle
Triple bond has the (blank) bond length
Shortest
Single bond has the (blank) bond energy
Lowest
Double bond has the (blank) bond energy
Middle
Triple bond has the (blank) bond energy
Highest
Bonds formed from the overlap of atomic orbitals
Valence bond theory
3 factors affect the overall energy of molecule
- Electron nuclei attraction
- nuclei nuclei repulsion
- electron electron repulsion
When 2 orbitals share a common region of space
Overlap
Covalent bond formed by overlapping end to end
Sigma bond
In a sigma bond, electron density is concentrated between the (blank) of the bonded atoms
Nuclei
Triple bonds are (blank) than single bonds
Shorter and stronger
Mixing or atomic orbitals to form special (hybrid) orbitals for bonding
Hybridization
Form new set of orbitals and give max overlap in correct geometry
Orbital hybridization
2 effective electron pairs
Hybridization =
Sp
3 effective electron pairs
Hybridization =
Sp2
4 effective electron pairs
Hybridization =
Sp3
5 effective electron pairs
Hybridization =
Sp3d
6 effective electron pairs
Hybridization =
Sp3d2
Sp3 hybridization =
1s orbital and 3 p orbitals
Double bond in ethylene consists of (blank) sigma bond and (blank) pi bond
1, 2
Determining bond order from molecular theory- hydrogen2 =
1
Determining bond order from molecular theory- helium2 =
0
Greater the (blank), the stronger and more stable the molecule
Bond order
Sp3 consists of
One S, 3 p
Sp2 consists of
One s, 2 p
Sp consists of
One S, one p
How many remaining unhybrid orbitals does sp3 have?
None
How many remaining unhybrid orbitals does sp2 have?
One p
How many remaining unhybrid orbitals does sp have?
Two p
Atomic orbitals to help explain bonding within molecules
Molecular orbital (MO) theory
Constructive interference means
Increased amplitude between nuclei
Destructive interference means
Node forms between the nuclei
S atomic orbitals can form
Sigma molecular orbitals
Three principles of molecular theory
1) # of MOs = # of atomic orbitals used
2) bonding MO is lower in energy than the atomic orbitals, the antibonding MO is higher
3) electrons assigned to MOs of successively higher energy
Bond order equation determined by MO
bonding e - # antibonding e divided by 2
How many electrons should be added to the MO diagram of the He2 molecule
4
