Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chem 115 > Chapter 9 > Flashcards

Chapter 9 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

What principle is VSEPR theory based on?

A

Electrons have negative charges and repel each other. Pairs of electrons are arranged about the central atom in ways to minimize repulsion’s between the pairs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does VSEPR stand for?

A

Valence-shell electron-pair repulsion theory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is electron-pair geometry?

A

The three-dimensional arrangement of bonding pairs and lone pairs of electrons about a central atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is meant by molecular geometry?

A

The 3D arrangement of the atoms in a molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Is electron-pair geometry and molecular geometry the same thing?

A

No, they may or may not be the same depending on the presence of lone pairs on the central atom. If there are no lone pairs then the electron-pair geometry and the molecular geometry is the same thing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the steric number?

A

The sum of both the number of atoms bonded to a central atom and the number of lone pairs of e;extrinsic on the central atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do you calculate the steric number (SN)?

A

SN = (# of atoms bonded to the central atom) + (# of lone pairs on central atom)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In a covalent compound with a steric number of 2, what is it’s electron-pair geometry and molecular geometry?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In a covalent compound with a steric number of 3, what is it’s electron-pair geometry and molecular geometry?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In a covalent compound with a steric number of 4, what is it’s electron-pair geometry and molecular geometry?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In a covalent compound with a steric number of 5, what is it’s electron-pair geometry and molecular geometry?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In a covalent compound with a steric number of 6, what is it’s electron-pair geometry and molecular geometry?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do we show 3D structures of a molecule on a 2D page?

A

We use a solid wedge to indicate a bond that comes out of a page and a dashed wedge to indicate a bond that goes behind the page and away from the viewer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do double bonds affect the ideal bond angles of Lewis diagrams?

A

Double bonds exert greater repulsion than a single bond. So in CH2O the bond angle between the H’s would be less than 120 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does adding lone pairs to the central atom affect the molecular geometry?

A
  • repulsion between lone pairs and bonding pairs is greater than the Repulsion between bonding pairs.
  • repulsion caused by a lone pair is greater than that caused by a double bond
  • repulsion caused by a double bond is greater than that caused by a single bond.
  • two lone pairs of electrons on a central atom exert a greater repulsive force on the atom’s bonding pairs than does one lone pair
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does a molecule with a SN of 3 and no lone pairs compare to a molecule with a SN of 3 and 1 lone pair?

A
17
Q

How does a molecule with at SN of 4 and no lone pairs compare to a molecule with a SN of 4 and 1 or 2 lone pairs?

A
18
Q

How does a molecule with at SN of 5 and no lone pairs compare to a molecule with a SN of 5 and 1, 2 or 3 lone pairs?

A
19
Q

How does a molecule with at SN of 6 and no lone pairs compare to a molecule with a SN of 6 and 1,2,3 or 4 lone pairs?

A
20
Q

What is a bond dipole?

A

The separation of electrical charge created when atoms with different electronegativities form a covalent bond

The unequal distribution of bonding electrons that produces a partial negative charge in one region of the bond and a partial positive charge in the other.

21
Q

What is a dipole moment (µ)

A

A measure of the degree to which a molecule aligns itself in a strong electric field. A quantitative expression of the polarity of a molecule.

A measure of the uneven distribution of electron density over the entire molecule

22
Q

What is a permanent dipole?

A

Found in molecules with multiple polar bonds around a center atom. The bond dipoles may combine to give the molecule an pverall polarity.

23
Q

What units are dipole moments expressed in?

A

debyes (D)

1 D = 3.34x10^-30 coulomb-meter

24
Q

What is a key characteristic of all nonpolar substances?

A

molecular symmetry

becasue symmetric orientation of bond dipoles means the dipoles completely offset one another, producing dipole moments of zero.

25
Q

what is valence bond theory?

A

a quantum mechanics-based theory of bonding that incorporates the assumption that covalent bonds form when half-filled orbitals on different atoms overlap or occupy the same region in space.

26
Q

what is a sigma (σ) bond?

A

a covalent bond to which atomic orbitals on adjoining atoms occupy the same region or space.

27
Q

What is a pi (π) bond?

A

A covalent bond in which electron density is greatest around - not along - the bonding axis. It forms from side-on overlap of two parallel p orbitals.

Chem 115 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions