Brainscape's Knowledge GenomeTM

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


See full index

chemistry > C6 - Shapes of molecules and intermolecular forces > Flashcards

C6 - Shapes of molecules and intermolecular forces 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 is electron pair repulsion theory?

A

Electron pairs repel each other so are arranged as far apart as possible
Arrangement minimises repulsion and therefore holds bonds in definite shape
Lone pairs repel more

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

Electron pair repulsion in increasing order?

A

Bond bond
Bond lone
Lone lone

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

What determines the shape of a molecule

A

The electron pairs surrounding the central atom

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

What does a solid line mean in displayed formula

A

Bond in the plane of paper

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

What does a solid wedge mean in displayed formula?

A

Comes out of the plane of paper

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

What does a dashed wedge mean in displayed formula

A

Goes into the plane of paper

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

Bond angle of tetrahedral

A

109.5

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

Bond angle of pyramidal

A

107

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

Bond angle of non linear

A

104.5

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

Bond angle of linear

A

180

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

Bond angle of trigonal planar

A

120

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

Bond angle of octahedral

A

90

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

Bond angle of trigonal bipyramidal

A

90
120

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

Electron pairs of octahedral

A

6bp

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

Electron pairs of linear

A

2bp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Electron pairs of tetrahedral

A

4bp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Electron pairs of non-linear

A

2bp
2lp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Electron pairs of trigonal planar

A

3bp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Electron pairs of pyramidal

A

3bp
1lp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is electronegativity

A

Ability of an atom to
attract electrons in a covalent bond

21
Q

How is electronegativity measured?

A

Paulings scale

22
Q

What happens to electronegativity down a group

A

Decreases

23
Q

What happens to electronegativity across a period

A

Increases

24
Q

What does it mean if the electronegativity difference is large?

A

One bonded atom has a much greater attraction for shared pair of electrons

25
Q

What is a non polar bond?

A

Bonded electron pair shared equally between bonded atoms

26
Q

When is a bond non polar

A

Bonded atoms are the same
Have same electronegativity value

27
Q

What is a pure covalent bond

A

Molecule of elements bonded to themselves

28
Q

What is a polar bond.

A

Bonded electron pair shared unequally between bonded atoms

29
Q

What’s a polar molecule

A

Molecule with overall dipole

30
Q

When is a bond polar?

A

Different elements with different electronegativity values

31
Q

What’s a dipole

A

Separation of opposite charges in a polar covalent bond
Creating a small positive charge and a small negative charge

32
Q

What’s a permanent dipole?

A

Small charge difference that does not change across a bond

33
Q

What are the three main categories of intermolecular forces

A

Induced dipole-dipole interactions (London forces)
Permanent dipole-dipole interactions
Hydrogen bonding

34
Q

Strength of intermolecular forces in increasing order

A

London forces
Permanent dipole-dipole interactions
Hydrogen bond
Single covalent bond

35
Q

How do London forces work?

A

Electrons move constantly producing instantaneous dipole that is constantly moving
Instantaneous dipole induces dipole on neighbouring molecule
Induced dipole induces further dipole on neighbouring molecules which attract one another
Temporary

36
Q

What does strength of London forces depend on

A

Size of molecule (number of protons/electrons)

37
Q

How do permanent dipole to dipole interactions occur?

A

Interact between two permanent dipoles of different molecules

38
Q

What are simple molecular lattice?

A

3D structure of molecules bonded together by weak intermolecular forces

39
Q

What are the melting points of simple molecular substances?

A

Low
weak intermolecular forces

40
Q

What is the solubility of non-polar simple molecular substances

A

Soluble in non-polar solvents as they can interact and form bonds
Interactions weaken intermolecular forces causing them to break and the compound dissolves

41
Q

What happens to non-polar simple molecule in a polar substance

A

Little interaction, intermolecular forces are too strong to be broken

42
Q

Explain solubility of polar simple molecule

A

Depends on strength of dipole, dissolves in polar solvents

43
Q

Do simple molecules conduct electricity

A

No as there are no charged particles that are free to move

44
Q

What is a hydrogen bond?

A

Strong dipole-dipole attraction between electron-deficient hydrogen atom on one molecule and a lone pair of electrons on a highly electronegative atom containing N, O, F on a different molecule

45
Q

What are anomalous properties of water

A

Ice is less dense that water:
-H bonds hold H2O molecules apart in open lattice structure
-Molecules held further apart in ice than water

46
Q

What is water’s melting point

A

High

47
Q

Why is water’s melting point high?

A

Has London forces and H bonds
H bonds require lot of energy to overcome

48
Q

What are other properties of water?

A

High surface tension
High viscosity

chemistry (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions