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Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals will depend upon the traits of the ‘parent’ orbitals.

Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

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Page 1: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

Hybrid Orbitals: atomic orbitals formed by blending different orbitals together

Just like with other hybrids, the characteristics of the hybrid orbitals will depend upon the traits of the ‘parent’ orbitals.

Page 2: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

Consider carbon…

How many valence electrons does carbon have? 4

According to its electron dot structure, how many unpaired electrons does carbon have?

C

What does carbon’s orbital filling diagram look like?

1s2 2s2 2p2

Atomic carbon only has 2 upaired

electrons!

Atomic carbon only has 2 upaired

electrons!

In order to form chemical bonds, carbon’s atomic orbitals must hybridize to form molecular orbitals.

Page 3: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

+

one s orbital one p orbital two sp hybrid orbitals (AX2)

one s orbital two p orbitals three sp2 hybrid orbitals (AX3)

+

one s orbital three p orbitals four sp3 hybrid orbitals (AX4)

+

Page 4: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

OHH

Sigma bonding

When two atomic orbitals (hybridized or not) overlap end-on, they form a single sigma bond.

+ H H

bond

AX2E2

+2 O

H H

sp3 + s bonds

H H

Page 5: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

Pi bonding

When two atomic orbitals overlap in a side-to-side fashion, they form a pi bond. Orbitals that form pi bonds are usually NOT hybridized.

OO

bond

bond

• Each oxygen had three sp2 hybrid orbitals and one p orbital.• The lone pairs are in sp2 orbitals, and the bond is formed by

the overlap of two sp2 orbitals.

• One unhybridized p orbital results in one pi bond.

• A sigma and a pi bond form a double bond.

Page 6: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

NN

bond

bond2 s

Multiple pi bonds

• Each nitrogen atom had two sp2 orbitals and two p orbitals.• The lone pairs went into an sp2 orbital on each nitrogen.• The bond was formed by the overlap of the remaining sp2

orbitals.• The two bonds were formed by the overlap of the two p

orbitals.

Page 7: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

Resonance Structures

Draw the stick structure for CO32- AX3 so sp2 hybrid.

2-

Draw the resonance structures for SO42-

C

O

OO

2-

S

O

O

O

O

2-

S

O

O

O

O

2-

S

O

O

O

O

AX4 so sp3 hybrid.

2-

C

O

OO

2-

C

O

O O

2-

S

O

O

O

O

: equivalent Lewis dot structures

Page 8: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

Polarity in bonding

• In covalent bonds, electrons aren’t always shared equally between the two nuclei.

• This is because some elements have a greater affinity for electrons than others.

Electronegativity: Ability of an atom to attract electrons when in a molecule. Electronegativity: Ability of an atom to attract electrons when in a molecule.

Page 9: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals
Page 10: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

When electrons in a covalent bond are concentrated near one of the nuclei, the bond is POLAR.

H F Polar bond

H H Nonpolar bond

If the electrons are shared equally between the nuclei, the bond is NONPOLAR.

+ -

Page 11: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

Because of the bent structure of water, water is a polar molecule.

O

HH

• Use arrows along the bonds to indicate the direction of the ‘pull’ on the electrons in the bond (the dipole moment).

• A plus-sign on the tail of the arrow shows that the bond is more positive at that end

Both bonds in water are polar.

How does this affect the polarity of the molecule?

• Add the two vectors (the arrows) together to find the net polarity (dipole moment) of the molecule

Page 12: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

All of the bonds in CCl4 are polar.

Is this molecule polar?C

ClCl Cl

Cl

Since the molecule is symmetrical, all of the dipoles along the bonds cancel each other out.

CCl4 is a nonpolar molecule and has no net dipole moment.

Page 13: Hybrid Orbitals: atomic orbitals formed by blending different orbitals together Just like with other hybrids, the characteristics of the hybrid orbitals

Are these planar molecules polar or nonpolar?

B

F

F

F

B

F

F

H

B

H

H

H

Are these linear molecules polar or nonpolar?

O C O C O S C O

nonpolar polar nonpolar

polar nonpolar polar