Knewton Alta 5.2 Hybridization

What type of bond is formed by the direct overlap of hybrid orbitals? a. a sigma bond b. a pi bond c. either a sigma or a pi bond d. an ionic bond

a. a sigma bond Recall that the direct overlap of hybrid orbitals forms σ bonds, and that the lateral overlap of unhybridized orbitals form a π bonds.

The hybrid orbitals have shapes/orientations that are _______ those of the isolated atoms' atomic orbitals. a. different from b. similar to c. equivalent to d. none of the above

a. different from When atoms are bonded in a molecule, their individual wave functions are combined. These hybrid orbitals are new orbitals that have new geometry compared to the individual atoms' atomic orbitals.

Rotation occurs freely around: a. single bonds b. double bonds c. triple bonds d. no covalent bond type

a. single bonds Only single bonds can rotate freely, as the overlap occurs directly on the internuclear axis, unlike double and triple bonds which are composed of both sigma and pi bonds, for which rotation would disrupt the orbital overlap.

What is the hybridization of carbon in carbon dioxide (CO2)? a. sp b. sp^2 c. sp^3

a. sp First, draw the lewis structure for CO2. The carbon atom in CO2 is surrounded by 2 regions of electron density, which become arranged in a linear electron-pair geometry. The hybridization for this linear arrangement is sp.

Which of the following statements about hybridization are true? a. hybrid orbitals exist in isolated atoms b. hybrid orbitals within the same atom have the same energy and shape c. hybrid orbitals are described mathematically as a linear combination of atomic orbitals d. an atom can have both hybridized and unhybridized orbitals at the same time

b. hybrid orbitals within the same atom have the same energy and shape c. hybrid orbitals are described mathematically as a linear combination of atomic orbitals d. an atom can have both hybridized and unhybridized orbitals at the same time Hybridization is a model used to describe the observed bonding in molecules. These hybrid orbitals are described mathematically by a process called LCAO, or the linear combination of atomic orbitals. The hybrid orbitals are equal in size, shape, and energy. sp and sp2 hybridization mixes 1 or 2 p orbitals with the s orbitals, while the remaining p orbital(s) do not form hybrid orbitals.

In order for a pi bond to form, there must be: a. direct overlap of p orbitals b. lateral overlap of p orbitals c. direct overlap of hybrid orbitals d. lateral overlap of hybrid orbitals

b. lateral overlap of p orbitals Any direct overlap is a sigma bond, and pi bonds are specifically the lateral overlap of unhybridized p orbitals.

In order for a pi bond to form, there must be: a. overlap of s orbitals b. overlap of unhybridized orbitals c. overlap of hybrid orbitals d. hybrid orbitals with different energies

b. overlap of unhybridized orbitals Pi bonds are created by the lateral overlap of unhybridized orbitals that contain at least one node along the internuclear plane, while sigma bonds occur through overlap of hybridized orbitals. Since s orbitals do not contain nodes, they cannot be involved in making pi bonds.

Unhybridized orbitals overlap to form: a. sigma bonds b. pi bonds c. sigma and pi bonds d. gamma bonds

b. pi bonds Unhybridized orbitals overlap to form pi bonds. Pi bonds form parallel to the bonded atoms and do not form a new hybrid orbital (unlike sigma bonds that form new hybrid orbitals linearly).

Direct overlap of hybrid orbitals yields a ____________ bond, and lateral overlap of unhybridized orbitals yields a ____________ bond. a. sigma, sigma b. sigma, pi c. pi, pi d. pi, sigma

b. sigma, pi Sigma bonds involve direct overlap of hybrid orbitals, while pi bonds involve lateral overlap of unhybridized orbitals.

Which statement best describes what occurs to the valence electrons in a CH4 molecule during hybridization? a. the valence electrons of the carbon atom are unequally allotted to the hybrid orbitals b. the valence electrons of the carbon atom are equally allotted to the hybrid orbitals c. the valence electrons of the carbon atom do not change in energy d. the valence electrons of the carbon atom are distributed to the sp^3 orbitals, except for one electron which remains in the 2p orbital

b. the valence electrons of the carbon atom are equally allotted to the hybrid orbitals The electrons are equally distributed to the sp3 orbital. These electrons rise in energy due to their redistribution to higher-energy orbitals but will ultimately be stabilized by interactions with the hydrogen atoms in CH4.

Which molecule has a central atom that is sp^2 hybridized? a. NH3 b. PCl3 c. BF3 d. CH4

c. BF3 The boron atom has three electron domains, so it will be sp2 hybridized.

Which of the following exhibits sp^3 hybridization? a. BH3 b. CH2O c. CCl4 d. all of the above

c. CCl4 CCl4 exhibits sp3 hybridization because the carbon atom has 4 electron domains.

The orbitals within a set of hybrid orbitals will have: a. equivalent shape but different energy b. equivalent energy but different shape c. equivalent shape and energy d. depends on the type of hybrid orbitals

c. equivalent shape and energy All orbitals within a set of hybrid orbitals will have identical shape and energy.

What is the difference between sp hybridization and sp2 hybridization? a. sp^2 hybridization involves only sigma bonds while sp hybridization involves only pi bonds b. there is no mixing between s and p orbitals in sp^2 hybridization, while these orbitals do mix in sp hybridization c. sp^2 hybridization produces orbitals that are oriented in a trigonal planar geometry while sp orbitals are linear d. sp^2 hybridization leaves one unhybridized p orbital while sp hybridization leaves two of these.

c. sp^2 hybridization produces orbitals that are oriented in a trigonal planar geometry while sp orbitals are linear d. sp^2 hybridization leaves one unhybridized p orbital while sp hybridization leaves two of these. One major difference between sp and sp^2 hybridization involves the geometry of the molecules. sp^2 hybridization produces orbitals that are oriented in a trigonal planar geomentry, while sp orbitals are linear. Additionally, sp^2 hybridization leaves only one unhybridized p orbital on the central atom, while sp hybridization leaves two. Both σ and π bonds may be present in both types of hybridization, and both involve the mixing of s and p atomic orbitals.

What is the hybridization of oxygen in water (H2O)? a. sp b. sp^2 c. sp^3

c. sp^3 First, draw the lewis structure for H2O. The oxygen atom in H2O is surrounded by 4 regions of electron density, which are arranged in a tetrahedral electron-pair geometry. The hybridization for this tetrahedral arrangement is sp3.

What is the hybridization of the oxygen atom in a water molecule? a. sp b. sp^2 c. sp^3 d. sp^3 d

c. sp^3 Oxygen will be sp^3 hybridized in a water molecule, because it is surrounded by four electron domains, and will thus need to hybridize all four of the orbitals in its valence shell.

sp hybridization is defined as a. the combination of an s orbital on one atom with a p orbital on a different atom b. the repulsion between the valence s orbital and valence p orbital on one atom c. the blending of the valence s orbital on an atom with one of the valence p orbitals on the same atom to create two equal sp orbitals d. the process by which a molecule changes shape

c. the blending of the valence s orbital on an atom with one of the valence p orbitals on the same atom to create two equal sp orbitals The sp hybridization process involves mixing of the valence s orbital with one of the valence p orbitals on the same atom to yield two equivalent sp hybrid orbitals.

Hybridization was developed to explain observations about: a. the energy contained in certain covalent bond b. the order in which orbitals are filled c. the bond angles in certain molecules d. none of the above

c. the bond angles in certain molecules From valence bond theory, bond angles in a molecule like water would be expected to be 90∘ rather than the observed 104.5∘, so hybridization was developed to understand these observations.

How many atomic orbitals are required to make a set of four hybrid orbitals? a. 1 b. 2 c. 3 d. 4

d. 4 A set of hybrid orbitals is generated by combining atomic orbitals. The number of hybrid orbitals in a set is always equal to the number of atomic orbitals that were combined to produce the set.

Four atomic orbitals will combine to give how many hybrid orbitals? a. 1 b. 2 c. 3 d. 4

d. 4 There will be the same number of hybrid orbitals in a set as the number of atomic orbitals that were combined to generate them.

Which of the following exhibits sp^2 hybridization? a. CCl4 b. BeCl2 c. CO2 d. BH3

d. BH3 BH3 exhibits sp^2 hybridization because the boron atom has 3 electron domains.

Which molecule is best described using hybrid orbitals? a. H2 b. Cl2 c. F2 d. NH3

d. NH3 Molecules with more than two atoms are best described using hybrid orbitals to form the covalent bonds.

In which of the following are hybrid orbitals formed? a. lone pair electrons b. the pi bond of double bonded atoms c. ionic atoms d. covalently bonded atoms

d. covalently bonded atoms Hybrid orbitals cannot exist in isolated atoms (because they are the result of bonded atoms) so they can only exist in covalently bonded atoms (i.e. sigma bonds).

The energy of an sp orbital will be: a. less than that of an s or p orbital b. greater than that of an s or p orbital c. less than that of an s orbital but greater than that of a p orbital d. less than that of a p orbital but greater than that of an s orbital

d. less than that of a p orbital but greater than that of an s orbital An sp orbital will have an energy in between those of the unhybridized s and p orbitals.