Bonding

Question 1

What is the octet rule?

Answer 1

Losing or gaining electrons to achieve noble gas configuration.

C, N, O, F, Na, Mg always abide by the octet rule!

Question 2

What is the formation of an ionic bond between?

(transfer of electrons)

Answer 2

Metal and nonmetal

Example: NaCl

Question 3

What is the formation of a covalent bond between?

(sharing of electrons)

Answer 3

2 nonmetals

Example: CO₂ (similar electronegativities)

Question 4

What kind of sharing of electrons occur in a nonpolar covalent bond? Polar covalent bond?

Answer 4

Nonpolar covalent bond: equal sharing of electrons

Polar covalent bond: unequal sharing of electrons

Question 5

[Mnemonic]

NEPA or NEPUN

(how to remember the sharing of electrons in nonpolar or polar covalent bonds)

Answer 5

NEPA or N E P U N

Nonpolar = equal sharing

Polar = unequal sharing

Question 6

What kind of bond forms between a Lewis acid and Lewis base?

Answer 6

Coordinate covalent bond

(a lone pair of one atom attacks another atom with an unhybridized p-orbital to form a bond)

Question 7

What are the four characteristics of ionic compounds?

Answer 7

1. high melting and boiling points
2. good conductors of heat and electricity
3. soluble in water
4. form crystal lattices (in solid state)

Question 8

Rank these bonds from longest to shortest:

C─C, C=C, C≡C

Answer 8

1. longest C─C
2. medium C=C
3. shortest C≡C

Bond strength is inversely related to bond length.

Question 9

What is bond energy?

Answer 9

Energy required to break a bond.

Single bond < Double bond < Triple bond

(Triple bonds have the greatest bond energy because more energy is required to break their bonds, in comparison to a single bond.)

Question 10

Bond energy = bond strength

Answer 10

Bond energy = bond strength

Example: Triple bonds have the greatest bond energy and strength.

Question 11

Sigma (σ) and pi (π) bonds are made from the overlap of two orbitals. Which kind of bonds does a single bond contain? Double bond? Triple bond?

Answer 11

Single bond: sigma

Double bond: 1 sigma and 1 pi

Triple bond: 1 sigma and 2 pi

Question 12

In a polar covalent bond, where are the positive and negative ends of a dipole?

Answer 12

Positive end: at the less electronegative atom

Negative end: at the more electronegative atom

Question 13

[Mnemonic]

Have No Fear Of Ice Cold Beer

(how to remember the seven diatomic elements)

They also form a seven on the periodic table with the exception of H.

Answer 13

Have No Fear Of Ice Cold Beer

H₂

N₂

F₂

O₂

I₂

C₂

Br₂

Question 14

How to calculate formal charge:

Answer 14

[Should - has]

Question 15

For resonance structures​, which structure is the most stable?

Answer 15

The one with the negative formal charge on the most electronegative atom.

Question 16

What are some exceptions to the octet rule?

Answer 16

Incomplete octet: H, He and Li (are all stable with 2 electrons), Be (4) and B (6)

Expanded octet: Period 3 and greater (stable with 8+ electrons)

Odd numbers of electrons: Example: NO which has 11 e^-

Question 17

What is the difference between electronic geometry and molecular geometry?

Answer 17

Electronic geometry: Count bonds and lone pairs

Molecular geometry: Count bonds

Example: CH₄, NH₃, and H₂O all have tetrahedral electronic geometry, but differ in their molecular geometry. CH₄ is tetrahedral, NH₃ is pyramidal, and H₂O is bent/angular.

Question 18

What is the molecular geometry for water?

Answer 18

Bent (or angular)

Question 19

What are the three kinds of intermolecular forces?

Answer 19

1. hydrogen bonding
2. dipole-dipole interactions (+ end of one molecule is attracted to the - end of another molecule and vice-versa)
3. London dispersion forces (VDW)

Dipole–dipole interactions are present in the solid and liquid phases but become negligible in the gas phase because of the significantly increased distance between gas particles.

Question 20

Which intermolecular force is the weakest?

Answer 20

London dispersion forces

(Causes temporary induced dipoles in a molecule and other molecules nearby which change and shift moment to moment. )

Question 21

Which intermolecular force is the strongest?

Answer 21

Hydrogen bonding

Question 22

Hydrogen bonding occurs when hydrogen is bound to which three atoms?

Answer 22

1. F
2. O
3. N