Ch. 7 Review

Resonance

100

Order these from strongest bond to weakest bond:

 C - C,  Li - O,  O = O,  C ≋ C

What is...

C≋C  >  O=O  >  C-C  >  Li-O

200

What is the formal charge of N, O_[1], and O_[2] in NO₂?

*Double Bond on O_[1]

What is...

N = 0

O₁ = 0

O₂ = -1

300

What is the formal charge of each element in F₂CO?

What is...

All FC are 0.

400

Draw the resonance for CO₃^-2.

What is... 

500

Draw the dominant Lewis structure for NCO^- and explain why it is the dominant structure.

What is...

Because more elements have a formal charge of 0, and oxygen has a negative charge because it is more electronegative than carbon or nitrogen. 

Polarity

100

Define the difference between a bond dipole and a molecular dipole.

What is...

Bond: separation of charge across a bond, or between two atoms

Molecule: separation of charge across a whole molecule

200

Draw the direction of electronegativity between atoms and indicate if the overall molecule is a dipole:

NH₃

What is...

It is a molecular dipole. 

300

Which of these contain polar bonds?

A. H₂O

B. CH₃

C. CCl₄

D. HCO₂

E. LiO₂

What is...

A. H₂O

C. CCl₄

D. HCO₂

400

The molecule XF3 has a dipole moment. Is X boron or sulfur?

What is...

X = Sulfur

500

Which molecule is polar and which is nonpolar?

SF₄, NH₃, H₃CH₂COH, CH₄, SO₂^-, C₆H₆

What is...

Nonpolar = SF₄, CH_4, C₆H₆

Polar = NH₃, H₃CH₂COH, SO₂^-

VSEPR & Lewis Structures

100

Draw the Lewis Dot Structure for: H₂S

...

200

What is the electronic geometry for O₃? Molecular? 

What is...

Electronic = Trigonal Planar

Molecular = Bent

300

What is the electron geometry and molecular geometry of CH₃⁺?

What is...

Both are trigonal planar. 

400

Name one atom that can have less than an octet and one that can have more.

What is...

Less = B, Be

More = S, P, Se, I, Xe

500

List the 5 VSEPR electron geometries and their bond angles.

What is...

Linear 180

Trigonal planar 120

Tetrahedral 109

Trigonal Bipyramid 120 & 90

Octahedral 90

Hybridization

100

Define hybridization.

What is...

mixing atomic orbitals to form new hybrid orbitals for pairing electrons

200

What is the hybridization around NO₃^-?

What is...

sp²

300

Write the VSEPR shape that goes with each:

sp, sp², sp³.

What is...

sp = linear

sp² = trigonal planar

sp³ = tetrahedral

400

What is the difference between sigma bonds and pi bonds? (Hint: think about bond types and how overlap occurs)

What is...

Sigma bonds are single bonds and are present in every bond. They are head-to-head overlap.

Pi bonds are double and triple bonds and are not present in every bond. They are side-to-side overlap.

500

Identify the hybridization around each circled atom.

What is...

1st C = sp³

2nd C = sp²

N = sp³