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Home , Lewis structure, Lone pair, Resonance (chemistry)

Worksheet 14 - Hybridization

The hybridized molecular orbitals have different shapes and energy levels than the atomic orbitals. The number of molecular orbitals created by hybridization depends on the number of atomic orbitals that are mixed to form them.

In forming sp3 hybridized orbitals, four atomic orbitals are mixed, one s and three p. The energy diagram for this process is shown below. The hybridized orbitals are higher in energy than the s orbital, but lower in energy than the p orbitals.

p energy sp3

s hybridization

atomic orbitals hybridized orbitals

Carbon has 4 . Add these electrons to the atomic and molecular orbitals. This hybridization gives tetrahedral geometry.

With this hybridization, C will form four equivalent σ bonds.

Draw a similar energy diagram for sp3 hybridized .

p energy sp3

s hybridization

How many σ bonds will be formed? 2 How are the other sp3 orbitals used? The other sp3 orbitals hold the oxygen lone pairs

Do the same for sp3 hybridized .

p energy sp3

s hybridization

In some Lewis structures, there are only three equivalent bonds formed. To create three equivalent hybridized orbitals, mix three atomic orbitals.

Draw and name the orbitals formed in this hybridization, then add the electrons for sulfur. Since the hybridized orbitals are close in energy, every orbital is filled with one before electrons are paired.

p p energy sp2

s hybridization

The hybridized orbitals will form __1___ σ bond(s).

The unhybridized orbital will form __1___ π bond(s).

There will be __2___ (s).

This hybridization gives trigonal planar geometry.

In linear , like CO2, the central has only two equivalent bonding orbitals. Draw the energy levels and name the orbitals formed in this hybridization.

p p energy sp

s hybridization

Fill in the electrons for carbon and determine the number and type of bonds formed. There will be 2 sigma bonds (with sp) and 2 pi bonds (with p)

In CO2, determine the hybridization of the oxygen . Complete the energy diagram for the . Draw the structure of CO2.

p p energy sp2 : : s hybridization

O: C O: Each oxygen atom forms 1 (with the sp2) and 1 (with the p) with the sp and p orbitals on the carbon atom In atoms with n=3 or larger, the d orbitals can also be hybridized. In molecules with five molecular orbitals, five atomic orbitals are mixed:

_d_ + _s_ + _p_ + _p_ + _p_

This will give trigonal bipyramidal geometry and is called dsp3 hybridization.

Finally, molecules with octahedral geometry, will have __6 __ molecular orbitals. This hybridization is called __d2sp3______.

Shown below is a portion of the chart from Worksheet 13. Fill in the hybridization for each of the compounds. compound bonds lone geometry shape hybridization pairs

bonds + lone pairs = 6 2 3 SF6 6 0 octahedral octahedral d sp

bonds + lone pairs = 4 3 NH3 3 1 tetrahedral trigonal sp pyramidal bonds + lone pairs = 6 - 2 3 ICl4 4 2 octahedral square d sp planar bonds + lone pairs = 4 3 CF4 4 0 tetrahedral tetrahedral sp

bonds + lone pairs = 3 2 SO3 3 0 trigonal trigonal sp planar planar bonds + lone pairs = 5 3 SF4 4 1 trigonal seesaw dsp bipyramidal bonds + lone pairs = 2 CO2 2 0 linear linear sp

bonds + lone pairs = 4 3 H2O 2 2 tetrahedral V-shaped sp

bonds + lone pairs = 3 - 2 NO2 2 1 trigonal V-shaped sp planar

Fill in the chart below and then complete the Lewis structures for the molecules shown below and fill in those charts.

element Lewis symbol # bonds # lone pairs C 4 0 C N 3 1 N H 1 0 H O 2 2 O F 1 3

1 H O σ bonds __7__ atom # bond angle hybridization 1 120 sp2 H C C OH π bonds __ 1__ 3 2 2 109 sp3 2 H 3 120 sp acetic

H H 1 atom # bond angle hybridization C C C N σ bonds _6___ 1 180 sp H 3 2 2 180 sp π bonds _3___ 2 acrylonitrile 3 120 sp

H 2 O H H CH σ bonds 25__ atom # bond angle hybridization 2 H C C N 1 120 sp N C π bonds 4__ 2 120 sp2 H C H 3 C C 1 3 109 sp O N N

H CH 3 H The shown to the left is riboflavin H (vitamin B2). Answer the following questions

HHO C about its structure. a) how many carbons are sp3 hybridized? 8 H C O H H O C H sp2 hybridized? 10

H C O H sp hybridized? 0 H C H H H HHC b) How many are sp3 hybridized? 2

H C CNN O C C C C sp2 hybridized? 2 H H C C C N C C NCH sp hybridized? 0 H H H O c) How many oxygens are sp3 hybridized? 4

sp2 hybridized? 2

sp hybridized? 0

d) How many σ bonds are there in total? 52

e) How many π bonds are there in total? 7

f) Which of the three rings are planar? The ring on the left, in which all carbon atoms are sp2 hybridized

- The ion, C2H3O2 , has both oxygens bonded to the same carbon.

a) Draw the and all forms.

H sp2 H sp3

O C C H O C C H

sp3 O H O H sp2 b) Label the hybridization around each carbon.

c) Pick one resonance structure and label the hybridization of each oxygen.

d) How many σ and π bonds are present? 6 sigma bonds, 1 pi bond

e) Which atom carries the formal negative charge? the oxygen with 3 lone pairs