Midterm 1

Question 1

Wavefunction (Y)

Answer 1

describes the current state of a quantum mechanical system (ex. electron)

Question 2

for each point x in space, |Y(x)^2| means…

Answer 2

the probability that the electron is at position x

Question 3

Node

Answer 3

zero probability of finding the electron here

Question 4

It doesn’t matter if Y(x) is pos. or neg. bc what matters is if…

Answer 4

|Y(x)^2| is large

Question 5

The ground state

Answer 5

The state with the lowest energy

Question 6

For hydrogen, the ground state is the…

Answer 6

1s state

Question 7

Degenerate

Answer 7

When multiple states have the same energy

Question 8

In a covalent bond, electrons are…

Answer 8

shared

Question 9

Valence Bond Theory

Answer 9

explains molecular geometry in terms of atomic orbitals while keeping the idea of localized electrons

Question 10

Molecular Orbital Theory

Answer 10

more accurate description because it allows electrons to be delocalized

Question 11

Heisenberg Uncertainty Principle

Answer 11

the more you know about the position of an electron, the less you know about its speed

Question 12

A bond is formed by…

Answer 12

overlapping two atomic orbitals

Question 13

For bonding, good overlap =

Answer 13

a stronger covalent bond

Question 14

Sigma bond

Answer 14

cylindrical symmetry around the bond axis

Question 15

Sigma bonds have high…

Answer 15

electron density along the bond axis

Question 16

Bonding diagrams

Answer 16

show the electron configuration of valence electrons of each atom and their bonding pairs

Question 17

Pi bonds

Answer 17

have a nodal plane that includes the bond axis

Question 18

Pi bonds have high…

Answer 18

electron density on either side of the bond axis

Question 19

Pi bonds are formed by…

Answer 19

side-by-side overlap of p-orbitals that are aligned with each other

Question 20

A single bond has…

Answer 20

one sigma bond

Question 21

A double bond has…

Answer 21

one sigma bond and one pi bond

Question 22

A triple bond has…

Answer 22

one sigma bond and two pi bonds

Question 23

Hybrid orbitals are…

Answer 23

degenerate

Question 24

Pi bonds hinder…

Answer 24

rotation around the C=C bond axis

Question 25

Molecular Orbitals

Answer 25

are built from linear combinations of atomic orbitals

Question 26

Bond Order equation

Answer 26

((# of e- in bonding MOs)-(# of e- in antibonding MOs))/2

Question 27

Homonuclear diatomics include...

Answer 27

Li2 to N2

Question 28

The number of molecular orbitals is...

Answer 28

ALWAYS the same as the number of atomic orbitals

Question 29

As bond order decreases,

Answer 29

bond energy decreases and bond length increases

Question 30

LUMO

Answer 30

lowest unoccupied molecular orbital

Question 31

HOMO

Answer 31

highest occupied molecular orbital

Question 32

In a nonpolar covalent bond,

Answer 32

the electron pair is evenly shared between both atoms

Question 33

In a polar covalent bond where one atom has a lower electronegativity than the other,

Answer 33

the bonding and antibonding molecular orbitals are uneven mixtures of atomic orbitals

Question 34

Use valence bond theory for...

Answer 34

sigma bonds

Question 35

Use molecular orbital theory for...

Answer 35

pi bonds

Question 36

Conjugated systems

Answer 36

are a collection of aligned p-orbitals that form extended molecular orbitals

Question 37

The HOMO-LUMO gap is...

Answer 37

the smallest amount of energy that the molecule can absorb

Question 38

Intramolecular forces

Answer 38

the chemical bonds that hold atoms together within a molecule

Question 39

ionic is ________ than covalent

Answer 39

stronger

Question 40

Intermolecular forces

Answer 40

interactions between molecules

Question 41

IMFS are responsible for...

Answer 41

cohesion between molecules

Question 42

Breaks IMFs

Answer 42

boiling

Question 43

A high boiling point indicates

Answer 43

strong IMFs

Question 44

London (Dispersion) Force

Answer 44

the interaction between the fluctuating dipoles

Question 45

Polarizability

Answer 45

the tendency of molecules to generate induced electric dipole moments when subjected to an electric field

Question 46

the larger the polarizability,

Answer 46

the larger the dipole moment

Question 47

Molecules with more electrons are...

Answer 47

more polarizable

Question 48

Heaver (larger) molecules have greater...

Answer 48

dispersion forces and boiling points

Question 49

Hydrogen bond

Answer 49

the favorable interaction between a polar bond including H and NOF

Question 50

Each water molecule can have up to...

Answer 50

four hydrogen bonds (tetrahedral order)

Question 51

Surface tension

Answer 51

the energetic cost of creating an interface

Question 52

Interface

Answer 52

the surface of a liquid where not all molecules are surrounded

Question 53

At the interface there are...

Answer 53

less favorable interactions than the molecules in the bulk liquid

Question 54

The stronger the surface tension,

Answer 54

the greater the IMFs of the liquid

Question 55

The lowest energy state of a fixed amount of liquid is a...

Answer 55

sphere (because it has the lowest surface-to-volume ratio)

Question 56

Benzyne is more reactive than benzene because the natural bond angle for sp hybridized species is

Answer 56

180 degrees but it has a hexagonal structure (120) at the bond angles (significant strain at triple bonded carbons)

Question 57

Conjugated bonds means...

Answer 57

longer wavelength

Question 58

11 conjugated bonds vs. 16 conjugated bonds:

Answer 58

16 conj. bond system would be weaker and have a slower wavelength, thus absorbing more red light. It will be bluer than the 11 conj. bond system and have a smaller HOMO-LUMO gap and lower energy.

Question 59

For polar molecules, valence electrons are pulled towards...

Answer 59

the more electronegative atom

Question 60

Moleules with a bond order greater than zero are..

Answer 60

stable

Question 61

Diamagnetic

Answer 61

electrons are paired

Question 62

Paramagnetic

Answer 62

electrons are unpaired