Chapter 5

Question 1

There are certain distances from the nucleus at which the probability density of finding an electron located at a particular orbital is ____

The value of the wavefunction ____ is ____ at this distance for this orbital

Such a value of radius r is called a ____ ____

Answer 1

Zero

ψ . . . zero

Radial node

Question 2

Instead of using numbers, the angular momentum quantum number is often designated by letters

For ℓ = 0: ____ orbital

For ℓ = 1: ____ orbital

For ℓ = 2: ____ orbital

For ℓ = 3: ____ orbital

Answer 2

s
p
d
f

Question 3

The number of radial nodes in an orbital is ____-____-____

For a 1s orbital (n = 1, ℓ = 0)
The number of nodes = 1 – 0 – 1 = 0
For a 2s orbital (n = 2, ℓ = 0)
The number of nodes = 2 – 0 – 1 = 1
For a 3s orbital (n = 3, ℓ = 0)
The number of nodes = 3 – 0 – 1 = 2

Answer 3

The number of radial nodes in an orbital is n – ℓ – 1

Question 4

The s subshell has a ____ ____.

The p subshell has a ____ ____.

The d and f orbitals are ____ ____.

These shapes represent the three-dimensional regions _________________________.

Answer 4

spherical shape

dumbbell shape

more complex

where the electron is likely to be found

Question 5

____ ____ developed valence bond theory in the 1930s
Recall that ____ ____ also came up with the electronegativity table

Answer 5

Linus Pauling

Question 6

Electrons reside in _____

____ ____ form when electrons are shared by the overlapping of singly occupied orbitals

Electrons in these orbitals must have ____ spins

Answer 6

orbitals

covalent bonds

opposite

Question 7

To form a covalent bond, an atom must have an ____ ____

Number of bonds formed by an atom is determined by the_______________

Theory works well for explaining bonding in diatomic molecules with only single bonds

Also helps explain the non-bonding behavior of ____ ____

Answer 7

unpaired electron

of unpaired electrons

noble gases

Question 8

The interaction of two hydrogen atoms changes as a ____ ____ ____

Energy of the system changes as the ____ ____

Lowest (most stable) energy occurs at a distance of 74 pm – the bond length observed for H2 molecules

Answer 8

function of distance

atoms interacts

Question 9

The ________________________ affects their overlap (but not for two s-orbitals)

Answer 9

The orientation of the orbitals also affects their overlap (but not for two s-orbitals)

Question 10

Greater overlap occurs when there is a ____ _____ between the two nuclei

Overlap is less when p-orbitals are ____________ to one another

Answer 10

direct line

at an angle

Question 11

What is a sigma bond? When does it occur? What is stronger a sigma bond or a pi bond?

Answer 11

Sigma bond: a covalent bond in which the electron density is concentrated in the region along the internuclear axis
(= single bond in Lewis structure language)

A sigma bond occurs when there is:
Overlap of two s-orbitals (eg., H2)
Overlap of an s-orbital and a p-orbital (eg., HCl)
Overlap of two p-orbitals (eg., Cl2)

Stronger than a pi (π) bond

Question 12

When does a pi bond occur? What is stronger a pi bond of a sigma bond?

Answer 12

A pi occurs when there is:
Side-by-side overlap of two p-orbitals
Lie on opposite sides of the internuclear axis
Along the axis is a node where there is no probability of finding an electron

Weaker than a sigma bond

Question 13

How do ions associate? What is the attraction of two ions a function of?

Answer 13

Dipole moments & ionic character

Ions associate via charge through a force called Coulombic (electrostatic) attraction

Attraction between two ions is a function of distance and magnitude of charge:

Question 14

What is the dipole moment?

Answer 14

Bond dipole moment highlights the separation of charge between atoms

Question 15

What is the dipole moment of a bond defined as?

Answer 15

The dipole moment of a bond is defined as the charge times the distance

Question 16

What is the attraction between two ions measured in?

Answer 16

This attraction is measured in a unit called the Debye

Question 17

Polar bonds are effectively ____ ____ ____
Compared with NaCl, HCl shows partial charge on the H (δ____) and the Cl (δ____)

Answer 17

partial ionic bonds

+ . . . -

Question 18

How is bonding in molecules best explained?

Answer 18

Bonding in other molecules is best explained with hybrid orbitals

Question 19

What needs to be kept in mind when working with hybrid orbitals?

Answer 19

The number of hybrid orbitals formed always equals the number of atomic orbitals that are combined.

Question 20

A water molecule has four regions of electron density, so VSEPR theory predicts a ____ arrangement of hybrid orbitals.

Two of the hybrid orbitals on oxygen contain____ ____, and the other two overlap with the 1s orbitals of hydrogen atoms to form the O–H bonds in H2O

This description is more consistent with the experimental structure.

Answer 20

tetrahedral

lone pairs

Question 21

Two atomic orbitals can hybridize to produce ____ hybrid orbitals

   one s orbital + one p orbital    -->    two \_\_\_\_\_\_ hybrid orbitals

Occurs when a central atom is surrounded by ____ regions of electron density.

Answer 21

Two atomic orbitals can hybridize to produce two hybrid orbitals

   one s orbital + one p orbital    -->   two sp hybrid orbitals

Occurs when a central atom is surrounded by two regions of electron density.

Question 22

Three atomic orbitals can hybridize to produce ____ hybrid orbitals

one s orbital + two p orbitals –> three ____ hybrid orbitals

Occurs when a central atom is surrounded by ____ regions of electron density

Answer 22

Three atomic orbitals can hybridize to produce three hybrid orbitals

one s orbital + two p orbitals –> three sp2 hybrid orbitals

Occurs when a central atom is surrounded by three regions of electron density

Question 23

As we know from the discussion of VSEPR theory, a region of electron density contains all of the electrons that point in one direction

____________, ______________, ________________, or _________ would each count as one region of electron density

Answer 23

As we know from the discussion of VSEPR theory, a region of electron density contains all of the electrons that point in one direction

A lone pair, an unpaired electron, a single bond, or a multiple bond would each count as one region of electron density

Question 24

Four atomic orbitals can hybridize to produce ____ hybrid orbitals

one s orbital + three p orbitals –> four ____ hybrid orbitals

Occurs when a central atom is surrounded by _____ regions of electron density

Answer 24

Four atomic orbitals can hybridize to produce four hybrid orbitals

one s orbital + three p orbitals –> four sp3 hybrid orbitals

Occurs when a central atom is surrounded by four regions of electron density

Question 25

Five atomic orbitals can hybridize to produce ____ hybrid orbitals one s orbital + three p orbitals + one d orbital --> five ____ hybrid orbitals Occurs when a central atom is surrounded by ____ regions of electron density.

Answer 25

Five atomic orbitals can hybridize to produce five hybrid orbitals one s orbital + three p orbitals + one d orbital --> five sp3d hybrid orbitals Occurs when a central atom is surrounded by five regions of electron density.

Question 26

Six atomic orbitals can hybridize to produce --> hybrid orbitals one s orbital + three p orbitals + two d orbitals --> six ____ hybrid orbitals Occurs when a central atom is surrounded by ____ regions of electron density.

Answer 26

Six atomic orbitals can hybridize to produce six hybrid orbitals one s orbital + three p orbitals + two d orbitals  six sp3d2 hybrid orbitals Occurs when a central atom is surrounded by six regions of electron density.

Question 27

Experimental data doesn’t always match____ We use hybridization when necessary to explain ____ ____ and observed (laboratory) measurements

Answer 27

theory We use hybridization when necessary to explain bond angles and observed (laboratory) measurements

Question 28

Single bonds are formed by the direct overlap __________________, p orbitals, or s orbitals These are called ____bonds The additional electrons shared in a multi bond are not a result of directly overlapping hybrid orbitals, but are a result of _____________________________________________________________________ Single bond = _______ bond Double bond =__________ bond Triple bond = _________ bond

Answer 28

Single bonds are formed by the direct overlap of two hybrid orbitals, p orbitals, or s orbitals These are called sigma (s) bonds The additional electrons shared in a multi bond are not a result of directly overlapping hybrid orbitals, but are a result of side-by-side overlap of two regular “p” atomic orbitals These are called pi (p) bonds Single bond = 1 sigma bond Double bond = 1 sigma bond, 1 pi bond Triple bond = 1 sigma bond, 2 pi bonds

Question 29

To determine the hybridization in molecules with multi bonds, recall that a double or triple bond is ___________________________

Answer 29

To determine the hybridization in molecules with multi bonds, recall that a double or triple bond is each one region of electron density