Bonding

Question 1

Quantum Numbers

Answer 1

describe the size, shape, orientation, an number of atomic orbitals an element possesses

Question 2

Principal quantum number

Answer 2

n; describes the energy level (shell) in which an electron resides and indicates the distance from the nucleus to the electron; its positive values range from 1 to infinity

Question 3

Azimuthal quantum number

Answer 3

l; determines the subshell in which an electron resides; its positive values rang from 0 to n -1. the subshell is often indicated with a letter; l=0 corresponds to s, 1 is p, 2 is d, and 3 is f

Question 4

Magnetic quantum number

Answer 4

m(l); determines the orbital in which an electron resides; its positive values range from -l to +l; different orbitals have different shapes; s-orbitals are spherical, while p-orbitals are dumbbell shaped and located on the x-, y-, or z-axis

Question 5

Spin quantum number

Answer 5

m(s); describes the spin of an electron; its possible values are +/- 0.5

Question 6

Bonding orbitals

Answer 6

created by head-to-head or tail-to-tail overlap of atomic orbitals of the same sign and are energetically favorable

Question 7

Anti bonding orbitals

Answer 7

created by head-to-head or tail-to-tail overlap of atomic orbitals that have opposite signs and are energetically unfavorable

Question 8

Single bonds

Answer 8

sigma bonds which contain two electrons

Question 9

Double bonds

Answer 9

contain one sigma bond and one pi bond

Question 10

Pi bonds

Answer 10

created by sharing of electrons between two unhybridized p-orbitals that align side by side

Question 11

Triple bonds

Answer 11

contain one sigma bond and two pi bonds

Question 12

Strength and length of bonds

Answer 12

multiple bonds are less flexible than single bonds; multiple bonds are shorter and stronger than single bonds, but individual pi bonds are weaker than individual sigma bonds

Question 13

sp3 hybridized orbitals

Answer 13

have 25% s character and 75% p character; they form tetrahedral geometry with 109.5 degree bond angles; carbons with all single bonds are sp3-hybridized

Question 14

sp2 hybridized orbitals

Answer 14

have 33% s character and 67% p character; they form trigonal planar geometry with 120 degree bond angles; carbons with one double bond are sp2 hybridized

Question 15

sp hybridized orbitals

Answer 15

have 50% s character and 50% p character; they form linear geometry with 180 degree bond angles; carbons with a triple bond, or two double bonds, are sp hybridized

Question 16

Resonance

Answer 16

describes the delocalization of electrons in molecules that have conjugated bonds

Question 17

Conjugation

Answer 17

occurs when single and multiple bonds alternate, creating a system of unhybridized p-orbitals down the backbone of the molecule through which pi electrons can delocalize

Question 18

Resonance and stability

Answer 18

Resonance increases the stability of a molecule