Chapter 5 Flashcards
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 ____ ____
Zero
ψ . . . zero
Radial node
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
s
p
d
f
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
The number of radial nodes in an orbital is n – ℓ – 1
The s subshell has a ____ ____.
The p subshell has a ____ ____.
The d and f orbitals are ____ ____.
These shapes represent the three-dimensional regions _________________________.
spherical shape
dumbbell shape
more complex
where the electron is likely to be found
____ ____ developed valence bond theory in the 1930s
Recall that ____ ____ also came up with the electronegativity table
Linus Pauling
Electrons reside in _____
____ ____ form when electrons are shared by the overlapping of singly occupied orbitals
Electrons in these orbitals must have ____ spins
orbitals
covalent bonds
opposite
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 ____ ____
unpaired electron
of unpaired electrons
noble gases
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
function of distance
atoms interacts
The ________________________ affects their overlap (but not for two s-orbitals)
The orientation of the orbitals also affects their overlap (but not for two s-orbitals)
Greater overlap occurs when there is a ____ _____ between the two nuclei
Overlap is less when p-orbitals are ____________ to one another
direct line
at an angle
What is a sigma bond? When does it occur? What is stronger a sigma bond or a pi bond?
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
When does a pi bond occur? What is stronger a pi bond of a sigma bond?
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
How do ions associate? What is the attraction of two ions a function of?
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:
What is the dipole moment?
Bond dipole moment highlights the separation of charge between atoms
What is the dipole moment of a bond defined as?
The dipole moment of a bond is defined as the charge times the distance
What is the attraction between two ions measured in?
This attraction is measured in a unit called the Debye
Polar bonds are effectively ____ ____ ____
Compared with NaCl, HCl shows partial charge on the H (δ____) and the Cl (δ____)
partial ionic bonds
+ . . . -
How is bonding in molecules best explained?
Bonding in other molecules is best explained with hybrid orbitals
What needs to be kept in mind when working with hybrid orbitals?
The number of hybrid orbitals formed always equals the number of atomic orbitals that are combined.
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.
tetrahedral
lone pairs
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.
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.
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
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
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
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
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
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
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.
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.
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.
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.
Experimental data doesn’t always match____
We use hybridization when necessary to explain ____ ____ and observed (laboratory) measurements
theory
We use hybridization when necessary to explain bond angles and observed (laboratory) measurements
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
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
To determine the hybridization in molecules with multi bonds, recall that a double or triple bond is ___________________________
To determine the hybridization in molecules with multi bonds, recall that a double or triple bond is each one region of electron density
