Chemistry chapter 8

How many σ-bonds are there in the molecule ethene, C2H4, whose orbital structure is shown below? Use a whole number in your answer

5

Hybridization predicts geometry best for:

small atoms Hybridization begins to break down in its ability to predict geometry as atoms get larger

Which of the following hybridizations is commonly associated with a linear geometry?

sp

What is the hybridization of C in CN−?

sp C in CN− has an sp hybridization because of its 2 regions of electron density (1 bonding, 1 non bonding).

The diagram shows energy levels for the unhybridized atomic orbitals for the carbon atom, as well as a set of orbitals for carbon in a molecule. The two orbitals enclosed in the dashed circle are what type of orbitals?

sp hybrid orbitals The lower two orbitals that are circled have energies that are intermediate between the atomic s and p orbitals, making them hybrid orbitals, and because there are two hybrids, they must correspond to two equivalent sp orbitals

What type of hybrid orbitals are shown below?

sp2 orbitals The number of hybrid orbitals in a set is equal to the number of atomic orbitals that were combined to produce the set. There are three hybrid orbitals shown, each at 120∘ angles from each other. These must form from the hybridization of one s orbital and two p orbitals, forming three sp2 hybrid orbitals

What is the hybridization of the oxygen atom in a water molecule?

sp3 Oxygen will be sp3 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.

What is the hybridization of oxygen in water (H2O)?

sp3 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 xenon atom in XeF6?

sp3d3 With six atoms and one lone pair, the seven total electron domains make it sp3d3 hybridized

Which of the following determines the strength of a covalent bond?

the amount of overlap for the orbitals involved

Hybridization was developed to explain observations about:

the bond angles in certain molecules

Which bond is strongest in a carbon-carbon triple bond?

the sigma bond

Which of the following describes a covalent bond as the overlap of half-filled atomic orbitals that yields a pair of electrons shared between two bonded atoms?

valence bond theory

Which molecule has a central atom that is sp3d hybridized?

BrF3 With two lone pairs and three single bonds, bromine has five electron domains which will make it sp3d hybridized.

The diagram below shows the orbitals of a carbon atom that are hybridized to form the ethene molecule, C2H4, with five regions of orbital density labeled A, B, C, D, and E. Which of the labeled lobes of electron density will form the π-bond or bonds of ethene?

C and E In ethene, one of the 2p orbitals remains unhybridized. It has two regions of electron density, shown in red and blue and labeled C and E in the figure. The unhybridized 2p orbital is used to form the π-bond. The 2s and two of the 2p orbitals hybridize to form the sp2 hybrid orbitals that have trigonal planar geometry. The sp2 hybrid orbitals are shown as the three equivalent orange regions of electron density labeled A, B, and D.

Which of the following exhibits sp3 hybridization?

CCl4

How many unhybridized p orbitals are there around the central atom of beryllium chloride, BeCl2?

First, draw the Lewis structure for BeCl2. There are 2 regions of electron density surrounding the central beryllium atom, which will arrange themselves in a linear geometry. Beryllium must be sp hybridized, and so there must be 2 unhybridized p orbitals in BeCl2.

Which of the following statements about hybridization are true?

Hybrid orbitals within the same atom have the same energy and shape. Hybrid orbitals are described mathematically as a linear combination of atomic orbitals. An atom can have both hybridized and unhybridized orbitals at the same time.

Which molecule has a central atom that is sp3d2 hybridized?

IF5 The iodine atom in IF5 has six electron domains, in the form of five single bonds and one lone pair, so it will be sp3d2 hybridized. ClF3 ,SF4, and PCl5 each have five electron domains, making the central atoms sp3d hybridized

Which of the following molecules has a nitrogen atom with an sp2 hybridization?

NO3− The NO3− molecule contains a nitrogen with 3 electron regions so its hybridization is sp2

Which of the following molecules will contain a node, or nodal plane, along the internuclear axis?

O2 N2

The orbital structure of the molecule acetylene, C2H2, is shown below. What do the dashed lines signify?

The four dashed lines indicate the formation of two π-bonds that are formed from the four unhybridized p orbitals

Which of the following has the correct number of s,p, and d orbitals to describe an octahedral arrangement?

The octahedral arrangement has one s, three p, and two d orbitals. The octahedral arrangement has six electron dense regions and is not possible for atoms in the first or second period of the periodic table.

Which molecule has a central atom that is sp3d2 hybridized?

XeF4 Only XeF4 will have six electron domains, in the form of four bonds and two lone pairs, so it will be sp3d2 hybridized.

A pi bond involves:

a node lateral orbital overlap

Which bond is the shortest?

carbon-oxygen triple bond

The hybrid orbitals have shapes/orientations that are _______ those of the isolated atoms' atomic orbitals.

different from

_______ is the process of combining wave functions for atomic orbitals.

hybridization

The energy of an sp orbital will be:

less than that of a p orbital but greater than that of an s orbital

If an atom has sp hybridization, what electron-pair geometry will it exhibit?

linear

In a sigma bond, the electron density is concentrated:

on the internuclear axis itself

A triple bond always consists of:

one sigma bond and two pi bonds

In the structure illustrating the bonding in ethene, C2H4, the two arrows point to what type of bond or bonds?

one π-bond with one lobe above and one lobe below the plane of the molecule

In order for a pi bond to form, there must be:

overlap of unhybridized orbitals

The diagram shows energy levels for the unhybridized atomic orbitals for the carbon atom, as well as a set of orbitals for carbon in a molecule. The two orbitals enclosed in the dashed circle are what type of orbitals

p orbitals

Which kind of orbitals can s orbitals overlap with?

s, p, and d

A pi bond involves:

side-by-side, or lateral orbital overlap with the electron density concentrated on opposite sides of the internuclear axis.