10/18 smartbook
The structure shown contains _____ σ bond(s) and _____ π bond(s).
-6 -2
A group of sp3 hybrid orbitals is formed by the hybridization of _____ s and _____ p orbital(s) from the valence shell of an atom.
one, three
Consider the combination of two atomic orbitals to form a pair of molecular orbitals, designated σ2sσ2s and σ∗2sσ2s*. Select all the statements that explain these designations correctly.
-The atomic orbitals that combine in this case are s orbitals. -Both orbitals are designated σ because they lie along the internuclear axis.
Which of the following aspects of bonding are addressed by valence bond theory, but are NOT addressed by Lewis bond theory?
-The energetics of bond formation -The differences in length between various single bonds
Select all the statements that correctly describe molecular bond order.
-The less stable the molecule, the lower the bond order will be. -The higher the MO bond order, the stronger the bond between the atoms will be.
A double bond is always made up of _____ σ and _____ π bond(s). A double bond is _____ than a single bond.
1;1; stronger
A triple bond is composed of _____ σ and _____ π bond(s).
1;2
The structure shown contains _____ σ bond(s) and _____ π bond(s). h c o
6,1
Select the partial orbital diagram that correctly shows the hybrid orbitals and electron distribution of the O atom in the molecule OF2.
B
Molecular orbital theory views bonding as the combination of atomic orbitals to form _____ orbitals, which belong to the molecule as a whole.
molecular
Match each term with the appropriate electron arrangement. paramagnetic diamagnetic
paramagnetic- one or more unpaired electrons present diamagnetic- No unpaired electrons present
A molecular species with one or more unpaired electrons in an MO is ______ and will be attracted to a magnetic field, whereas a species with no unpaired electrons in its MOs is ______ and will be slightly repelled by a magnetic field.
paramagnetic; diamagnetic
Molecular orbitals formed from the combination of atomic s orbitals are called _______ molecular orbitals because they are cylindrically symmetrical. The molecular orbitals formed from atomic 1s orbitals are designated sigma*1s for the ______ molecular orbitals and sigma 1s for the _____ molecular orbital
sigma antibonding bonding
Which of the following statements correctly describe sp3 hybrid orbitals? Select all that apply.
- An sp^3 orbital is unsymmetrical in shape, having one small and one large lobe. -The four sp^3 hybrid orbitals of a group are equivalent in shape and energy.
Which of the following options correctly describe a molecular orbital (MO) energy-level diagram? Select all that apply.
- The MO diagram typically includes valence-shell molecular orbitals only. - The MO diagram can be used to calculate bond order and predict the stability of a species. - The MO diagram shows the relative energy and number of electron in each MO.
Select all the statements that correctly describe the bonding in the molecule PF3 in terms of valence bond theory.
-Each P-F bond is formed by the overlap of a 3p orbital from P with a 2p orbital from F. -VB theory predicts that the bond angles in PF3 will be close to 900.
Which of the following statements are correct with regard to Lewis bonding theory and valence bonding theory?
-Valence bond theory can make predictions about bond angles that Lewis theory cannot. -Lewis theory does not explain differences in bond strength, while valence bond theory does.
Which of the following is the correct equation for calculating molecular orbital bond order? (MO is an abbreviation for molecular orbital.)
1/2 [(# of e- in bonding MO) - (# of e- in antibonding MO)]
Select the partial orbital diagram that correctly shows the hybrid orbitals and electron distribution of the N atom in the molecule NBr3.
C
Match each type of bond with its ability to allow rotation.
sigma- allows free rotation pi-restricts
A group of hybrid orbitals formed by the hybridization of s and p orbitals from the valence shell of an atom all have the same ______ and _______.
size, shape
Which of the following statements correctly describe a π bond? Select all that apply.
-A π bond is formed by the side-to-side overlap of two p orbitals. -A multiple bond always contains at least one π bond.
Select all the statements that correctly describe a σ bond.
-All single bonds are σ bonds. -A σ bond results from end-to-end (direct) overlap of two orbitals.
The valence molecular orbital diagram for Be2+ is shown. Which of the following statements correctly interpret this diagram? Select all that apply.
-Be2+ has a weaker bond than H2. -The MO bond order for Be2+ is 1/2. -Be2+ is more likely to exist than Be2.
The combination of one s and two p orbitals will form a group of three _____ hybrid orbitals. These hybrid orbitals adopt a(n) _____ planar geometry and are at an angle of _____ o to the remaining unhybridized p orbital.
-sp2 -trigonal -90
Molecular orbitals that lie along the internuclear axis are called _____ MOs because they are cylindrically symmetrical. The MOs formed from atomic 1s orbitals are designated σ∗1sσ1s* for the _____ MO and σ1sσ1s for the Blank 3Blank 3 bonding , Correct Unavailable MO.
sigma antibonding bonding
Match the hybridization of the central atom with the number of electron domains surrounding it.
sp- 2 electron domains sp3d- 5 electrons sp2- 3 electrons sp3- 4 electrons sp3d2- 6 electroms
In the structure shown, the C atom is _____-hybridized while the O atom marked 2 is _____-hybridized.
sp2, sp3
A bond in which the shared electron density is concentrated along the axis between the bonding nuclei is called a(n) _____ bond.
-sigma
The valence molecular orbital diagram for Li2- is shown. The molecular orbital bond order for this species is equal to _____ and Li2- is _____ stable than Li2.
-1/2, less
Which of the following statements correctly describe bonding and antibonding molecular orbitals? Select all that apply.
-A bonding MO is formed by constructive combination of two atomic orbitals. -A bonding MO is lower in energy than the original atomic orbitals. -An antibonding MO has two lobes and does not lie between the bonding nuclei.
Select all the statements that correctly describe the hybridization model of bonding.
-A covalent bond can be formed when a hybrid orbital from one atom overlaps with an orbital from another atom. -Before a covalent bond forms, atomic orbitals from a specific atom mix or hybridize to form hybrid orbitals.
Which of the following statements correctly describe the formation of sp2 hybrid orbitals? Select all that apply.
-A group of sp2 hybrid orbitals assumes a trigonal planar geometry. -The formation of sp2 hybrid orbitals leaves one unhybridized valence p orbital.
Select all the statements that correctly describe sp hybrid orbitals.
-Each sp hybrid orbital has one large and one small lobe. -The angle between two sp hybrid orbitals is 180o.
Select all the statements that correctly describe the bonding in the molecule HCl in terms of valence bond theory.
-The H-Cl bond is formed by the overlap of a 3p orbital from Cl with a 1s orbital from H. -Valence bond theory predicts the potential energy is a minimum for an optimal orbital overlap for H and Cl.
Select all the statements that correctly describe the bonding in a covalently bonded species using hybridization.
-The ground-state electron configuration of the atom shows the orbitals available for hybridization. -The number of electron domains around the atom determines the number of hybrid orbitals required.
The valence molecular orbital diagram for the cation F2+ is shown. Which of the following options correctly interpret this diagram? Select all that apply.
-The molecular orbital bond order is equal to 3/2 -F2+ has a stronger bond than F2.
Select all the statements that correctly describe the general principles of molecular orbital theory.
-Two atomic orbitals combine to form two molecular orbitals. -Bonding involves the formation of new orbitals that belong to the molecule as a whole.
Which of the following statements correctly describe the rules used for placing electrons in molecular orbitals? Select all that apply. (MO is an abbreviation for molecular orbital.)
-lower energy orbitals are filled before placing electrons in higher energy orbtials -if two MOs have equal energy, an electron must be placed in each orbital before pairing up -orbitals are filled in order of increasing energy
For an atom surrounded by 5 or 6 electron groups, hybrid orbitals are formed by combining _____ s orbital(s), _____ p orbital(s) and 1 or 2 _____ orbitals.
-one -three -d
A _____ bond restricts rotation about the bond axis while a _____ bond allows almost free rotation.
-pi -sigma
A bond formed by sideways overlap of two p orbitals (one from each bonding atom) is called a(n) _____ bond. This type of bond _____ has region(s) of electron density.
-pi -two
The hybridization of one s and one p orbital will result in the formation of two _____ , hybrid orbitals. This will leave _____ unhybridized valence p orbital(s), which is/are at right angles to the hybrid orbitals.
-sp -two
Select all the statements that correctly describe hybridization involving d orbitals.
-the hybridization of one s, three p and one d orbital gives five sp3d orbitals -A group of six sp3d orbitals will have an octahedral arrangement -when sp3d orbitals are formed there will be four unhybridized d orbitals remaining
Arrange the steps for describing the bonding of a given molecule using hybridization. Place the first step at the top of the list.
1. draw a lewis 2. the number of electron... 3. combine the necessary... 4. place electrons ...
Match each type of orbital hybridization with the corresponding geometry. sp sp2 sp3 sp3d sp3d2
1. linear 2. trigonal planar 3.tetrahydral 4.trigonal bipyramidal 5.octahedral
Which of the following statements correctly defines hybrid orbitals?
Orbitals used for bonding that are formed by mixing atomic orbitals from the same atom
Match each structure shown with the correct hybridization for the central atom. a- xe f b- c cl h c- c o d- s o
a- sp3d2 b-sp3 c-sp d-sp2
The valence molecular orbital diagram for the anion B2- is given. Which of the following options correctly interpret this diagram? Select all that apply.
b2- is paramagnetic b2- has a shorter bond than b2 the molecular orbital bond order is equal to 3/2
The molecular orbital bond order is calculated as 1212(x - y), where x is the number of electrons in _____ molecular orbitals and y is the number of electrons in _____ molecular orbitals. In general, the higher the molecular orbital bond order, the _____ the bond strength for the species.
bonding; antibonding; greater
A molecular orbital is a region of space in a covalent species where electrons are likely to be found. The combination of two atomic orbitals always forms two molecular orbitals; the bonding molecular orbital, which is _____ in energy, and the antibonding molecular orbital, which is _____ in energy, than the original atomic orbitals.
lower, higher
The lower the molecular orbital bond order, the _____ the bond and the _____ stable the species.
weaker, less
