Chem 111 chapter: 7.4-7.6 (Valence bond theory, hybridization of atomic orbitals, and hybridization in molecules containing multiple bonds)

A triple bond is composed of _____ σ and _____ π bond(s).

1, 2

In general, the hybridized bonding in a molecule can be described using the 6 following steps:

1. Draw the Lewis structure 2. Count the number of electron domains on the central atom. This is the number of hybrid orbitals necessary to account for the molecule's geometry 3. Draw the ground-state orbital diagram for the central atom 4. Maximize the number of unpaired valence electrons by promotion 5. Combine the necessary number of atomic orbitals to generate the required number of hybrid orbitals 6. Place electrons in the hybrid orbitals, putting one electron in each orbital before pairing any

A double bond is stronger than a single bond, but not twice as strong. Select the statement that correctly explains this observation. A. A π bond is not as strong as a σ bond because sideways overlap of orbitals is less effective than direct head-to-head overlap. B. A π bond is stronger than a σ bond because it has two regions of orbital overlap instead of one. C. A π bond is weaker than a σ bond because the electrons in p orbitals repel each other more strongly.

A A. A π bond is not as strong as a σ bond because sideways overlap of orbitals is less effective than direct head-to-head overlap.

Hybridization of the s orbital and the three p orbitals yields ______ hybrid orbitals designated _______

four sp³

Hybridization of the s orbitals, the three p orbitals, and one of the d orbitals yields _________ orbitals that are designated _________

hybrid; sp³d

(hybridization) shape and energy is ____________ the orbitals that were combined

in between

chemical equation must be balanced so that the ______________________________ is obeyed

law of conservation of mass

(corresponding geometry) sp

linear

(valence bond theory) Formation of a bond results in _________ potential energy for the system

lower

(hybridization) orbitals have a new or the same shape and energy?

new

(hybridization) does the number of orbitals change?

no

the type of hybridization depends on the...

number of electron domains

Hybrid orbitals are designated by using a superscript to indicate the ___________ of each type of orbital used to form them. For example, the designation sp² indicates that _________ s and _________ p orbitals were combined to form this orbital type

number; one; two

(corresponding geometry) sp³d²

octahedral

_______ hybrid orbital(s) is/are needed for each electron domain

one

(valence bond theory) The two electrons share in the region of the orbital overlap must be of __________ spin

opposite

Because the p orbitals that form pi bonds must be parallel to each other...

pi bonds restrict the rotation of a molecule in a way that sigma bonds do not

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; 2

According to the valence bond theory, a covalent bond will form between two atoms if the ___________ _______ of the resulting molecule is ________ than the combined potential energies of the isolated atoms

potential energy; lower

Hybridized orbitals form ______ bonds and unhybridized orbitals form ________ bonds

sigma; pi

(valence bond theory) A bond forms when ________ occupied atomic orbitals on two atoms __________

singly; overlap

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

an excited state is generally denoted with a _______

star or *

(corresponding geometry) sp³

tetrahedral

hybridization

the mixing of atomic orbitals

An s atomic orbital and two p atomic orbitals combine to from _____ ________ hybrid orbitals

three sp²

(corresponding geometry) sp³d

trigonal bipyramidal

(corresponding geometry) sp²

trigonal planar

one sigma bond and two pi bonds make a ________ bond

triple

(true or false) The four sp3 hybrid orbitals of a group are equivalent in shape and energy.

true

Pi bonds are the sideways overlap of _______________ p orbitals

unhybridized

Can a hybridized orbital also hold a lone pair?

yes

How does the hybridization model account for the differences between the geometry of atomic orbitals (s and p orbitals) and observed molecular geometries? A. Unlike atomic orbitals, hybrid orbitals have spatial orientations that conform to experimentally-determined molecular geometries. B. Hybrid orbitals may hold more than two electrons. C. Unlike atomic orbitals, all nonbonded hybrid orbitals are singly occupied and available for bonding. D. Hybrid orbitals are linear combinations of atomic orbitals to yield orbitals that are equivalent in energy and shape.

A and D A. Unlike atomic orbitals, hybrid orbitals have spatial orientations that conform to experimentally-determined molecular geometries. D. Hybrid orbitals are linear combinations of atomic orbitals to yield orbitals that are equivalent in energy and shape.

pi bond (π bond)

A bond that forms from the interaction of parallel p orbitals

Sigma bond (σ bond)

A bond which the shared electron density is concentrated directly along the internuclear axis

Valence bond theory

Atoms share electrons when an atomic orbital on one atom overlaps with an atomic orbital on the other. Each of the overlapping atomic orbitals must contain a single, unpaired electron

Which of the following statements correctly describe a π bond? Select all that apply. A. A π bond concentrates electron density along the axis between two nuclei. B. A π bond is formed by the side-to-side overlap of two p orbitals. C. A multiple bond always contains at least one π bond. D. A π bond holds two electrons, one in each region of the bond.

B and C B. A π bond is formed by the side-to-side overlap of two p orbitals. C. A multiple bond always contains at least one π bond.

How does hybridization of atomic orbitals allow us to reconcile valence bond theory with VSEPR theory? A. Hybridization enables us to predict the shapes of molecules. B. Hybridization of atomic orbitals produces orbital shapes and spatial orientations that correlate to those predicted in VSEPR theory. C. Hybridized atomic orbitals produce new mixed orbitals that extend over the entire molecule. D. Hybridization enables us to account for the number of singly-occupied orbitals required for bonding.

B and D B. Hybridization of atomic orbitals produces orbital shapes and spatial orientations that correlate to those predicted in VSEPR theory. D. Hybridization enables us to account for the number of singly-occupied orbitals required for bonding.

Select all the statements that correctly describe a σ bond. A. A σ bond concentrates electron density above and below the plane of the two bonded atoms. B. A σ bond can only result from the overlap of p orbitals. C. All single bonds are σ bonds. D. A σ bond results from end-to-end (direct) overlap of two orbitals.

C and D C. All single bonds are σ bonds. D. A σ bond results from end-to-end (direct) overlap of two orbitals.

Which of the following statements is true about the orbitals that hybridize in the central atom of PF3? A. The 3s orbital, three 3p orbitals, and one 3D orbital in the P atom hybridize to form five hybrid orbitals, all fo equal energy. B. One of the sp³d hybridized orbitals contain a lone pair of electrons. C. The three, hybridized sp² orbitals result in 120 degree F-P-F bond angles D. The four, hybridized sp³ orbitals repel each other to create the molecule's tetrahedral electronic geometry E. There is an empty hybridized orbital on the central P in this atom

D. The four, hybridized sp³ orbitals repel each other to create the molecule's tetrahedral electronic geometry

Why is rotation about a π bond restricted?

Free rotation would disrupt the parallel arrangement of the p orbitals, causing the bond to break.

hybrid orbitals

Orbitals formed by hybridization of some combinations of s, p, or d atomic orbitals

_____________ of matter are included in balanced equations

States

(hybridization) # of electrons does/does not change

does not

(hybridization) of orbitals does/does not change

does not

(true or false) A multiple bond always contains at least one π bond.

True

hybridization occurs in _______ ______ in _______

bonded atoms; molecules

Hybridization of atomic orbitals can occur for observed bond angles in molecules that could/could not be described by the direct over lap of orbitals

could not