Brainscape's Knowledge GenomeTM

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


See full index

CHEMISTRY > Bonding And Structure > Flashcards

Bonding And Structure Flashcards

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

What are ions?

A

Charged particles that are formed when an atom loses or gains electrons

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

What is the charge of the ion when electrons are gained?

A

Negative
Positive when electrons are lost

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

What are molecular ions?

A

covalently bonded atoms that lose or gain electrons

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

Which electrons are lost when an atom becomes a positive ion?

A

Electrons in the highest energy levels

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

Do metals usually gain or lose electrons?

A

lose electrons

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

Which are the 4 elements that don’t tend to form ions and why?

A

-Beryllium, boron, carbon and silicon
- Requires a lot of energy to transfer outer shell electrons

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

What are the 3 main types of chemical bonds?

A
  • Ionic
  • Covalent
  • Metallic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define ionic bonding

A

The electrostatic attraction between positive and negative ions

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

Give an example of an ionically bonded substance

A

NaCl – salt

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

What determines the strength of an ionic bond?

A
  • ionic radius and ionic charge
  • ionic bonding is stronger and the melting points higher when the ions are smaller and/ or have higher charges
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Explain the trend in ionic radius down a group

A
  • ionic radii increases going down a group
  • This is because down a group the ions have more shells of electrons
  • Thus the outermost electron experience less pull from positive nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Explain the trend in ionic radius for this set of isoelectronic ions [ N3-, O2-, F+, Ne, Na+, Mg2+, Al3+

A

-There are increasing numbers of protons from N to F and then Na to Al but the same number of electrons
- Therefore nuclear attraction between the outermost electrons and nucleus increases and ions get smaller

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

What are the physical properties of ionic compounds?

A
  • high melting points
  • non-conductor or electricity when solid
  • Conductor of electricity when in solution or molten
  • Brittle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In a solution of CuCro4 with connected electrodes which electrode will the 2 ions migrate to?

A

Cu2+ migrates to the negative electrode
CrO4 ^{2-} migrates to the positive electrode

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

Define covalent bonding

A

electrostatic attraction between a shared pair of electrons and the nuclei

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

Define metallic bonding

A

electrostatic attraction between the positive metal ions and the sea of delocalized electrons

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

Electrons in which shell are represented in a dot and cross diagram?

A

The outer shell

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

Why does giant ionic lattices conduct electricity when liquid but not when solid?

A

-In solid state the ions are in fixed positions and thus cannot move.
- When they are in liquid state the ions are mobile and thus can freely carry the charge

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

Giant ionic lattices have high or low melting and boiling points? Explain the answer

A

They have high melting and boiling points because a large amount of energy is required to overcome the electrostatic bonds

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

In what type of solvents do ionic lattices dissolve?

A

Polar solvents e.g. Water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why are ionic compounds soluble in water?

A

Water has a polar bond. Hydrogen atoms have a +ve charge and oxygen atoms have a -ve charge. These charges are able to attract charged ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is it called when atoms are bonded by a single pair of shared electrons?

A

A single bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How many covalent bonds does carbon form?

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How many covalent bonds does oxygen form?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the effect of multiple covalent bonds on bond length and strength?

A

Double/ triple bonds exert greater electron density therefore the attraction between the nucleus and electron is greater resulting in a shorter and stronger bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a lone pair?

A

Electrons in the outer shell that are not involved in the bonding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is formed when atoms share two pairs of electrons?

A

Double bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is formed when atoms share three pairs of electrons?

A

Triple bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a dative covalent bond?

A

A bond where both of the shared electrons are supplied by one atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How are oxonium ions formed?

A

Formed when acid is added to water. H3O+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does expansion of the octet mean?

A

When a bonded atom has more than 8 electrons in the outer shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the types of covalent structure?

A
  • Simple molecular lattice
  • Giant covalent lattice
33
Q

Describe the boding in simple molecular structures

A

Atoms within the same molecule are held by strong covalent bonds and different molecules are held by weak intermolecular forces

34
Q

Why do simple molecular structures have low melting and boiling points?

A

small amount of energy is enough to overcome the intermolecular forces

35
Q

Can simple molecular structures conduct electricity?

A

No, they are non-conductors

36
Q

Why do simple molecular structures not conduct electricity?

A

The have no free charged particles to move around

37
Q

Simple molecular structures dissolve in what type of solvent?

A

Non- polar solvents

38
Q

Give examples of giant covalent structures

A
  • Diamond
  • Graphite
  • Silicon dioxide, SiO2
39
Q

List some properties of giant covalent structures? (3)

A
  • High melting and boiling points
  • Non-conductors of electricity, except graphite
  • Insoluble in polar and non-polar solvents
40
Q

Why does graphite conduct electricity?

A

Delocalized electrons present between the layers are able to move freely carrying charge

41
Q

Why do giant covalent structures have high melting and boiling points?

A
  • Strong covalent bonds within the molecules need to be broken which requires a lot of energy
42
Q

Describe the structure of Diamond

A

3D tetrahedral structure of C atoms, with each C atom bonded to four others

43
Q

what does the shape of a molecule depend on?

A
  • Number of electron pairs in the outer shell
  • Number of these electrons which are bonded and lone pairs
44
Q

what is the shape, diagram and bond angle for BeCl2

A

Linear, 180 degrees

45
Q

What is the shape, diagram and bond angle for BCl3?

A

Trigonal Planar, 120 degrees

46
Q

What is the shape, diagram and bond angle for CH4?

A

Tetrahedral, 109.5 degrees

47
Q

What is the shape, diagram and bond angle for PCl5?

A

Trigonal bipyramid, 90 degrees and 120 degrees

48
Q

What is the shape, diagram and bond angle for SF6?

A

Octahedral, 90 degrees

49
Q

What is the shape, diagram and bond angle for NH3?

A

Pyramidal, 107 degrees

50
Q

What is the shape, diagram and bond angle for H2O?

A

Non-linear, 104.5 degrees

51
Q

What is the shape, diagram and bond angle for NH4 {+}

A

Tetrahedral, 109.5 degrees

52
Q

By how many degrees does each lone pair reduce the bond angle?

A

2.5 degrees

53
Q

Define electronegativity

A

The ability of an atom to attract the pair of electrons (the electron density) in a covalent bond

54
Q

what scale is electronegativity measured on?

A

Pauling scale

55
Q

In which direction of the periodic table does electronegativity increase?

A

Top right, towards fluorine

56
Q

What does it mean when the bond is non-polar?

A

The electrons in the bond are evenly distributed?

57
Q

What is the most electronegative element?

A

Fluorine

58
Q

How is a polar bond formed?

A

Bonding atoms have different electronegativities

59
Q

Why is H2O polar, whereas CO2 is non-polar?

A

CO2 is a symmetrical molecule, so there is no overall dipole

60
Q

what is meant by intermolecular force?

A

Attractive force between neighboring molecules

61
Q

What are the 2 types of intermolecular forces?

A
  • Hydrogen bonding
  • Permanent dipoles
  • London forces
62
Q

Describe permanent dipole-induced dipole interactions

A

When a molecule with a permanent dipole is close to other non polar molecules it causes the non-polar molecule to become slightly polar leading to attraction

63
Q

Describe permanent dipole- permanent dipole interactions

A

some molecules with polar bonds have permanent dipoles —> Forces of attraction between those dipoles and those of neighboring molecules

64
Q

Describe London Forces

A
  • London forces are caused by random movements of electrons
  • This leads to instantaneous dipoles
  • Instantaneous dipole induces a dipole in nearby molecules
  • induced dipoles attract one another
65
Q

Are London forces greater in smaller or larger molecules?

A

Larger due to more electrons

66
Q

Does boiling point increase of decrease down the noble gas group? Why?

A

Boiling point increases because the number of electrons increases and hence the strength of London forces also increases

67
Q

What conditions are needed for hydrogen bonding to occur?

A

-O-H, N-H or F-H bond, lone pair of electrons on O, F, N
- Because O, N and F are highly electronegative, H nucleus is left exposed
- Strong force of attraction between H nucleus and lone pair of electrons on O, N, F

68
Q

Why is ice less dense than liquid water?

A
  • In ice, the water molecule are arranged in an orderly patter. it has an open lattice with hydrogen bonds
  • In water, the lattice is collapsed and the molecules are closer together
69
Q

Why does water have a melting/ boiling point higher than expected?

A

hydrogen bonds are stronger than other intermolecular forces so extra strength is required to overcome the forces

70
Q

What type of intermolecular forces do alkanes have? Why?

A

London Force => Induced dipole-dipole interaction, because the bonds are non-polar

71
Q

What happens to the boiling point as alkane chain length increases? Why?

A
  • The boiling point increases because there is more surface area and so more number of induced dipole-dipole interaction
  • Therefore more energy is required to overcome the attraction
72
Q

Does a branched molecule have lower or higher boiling point compared to equivalent straight chain? Why?

A
  • The branched molecule has a lower boiling point because they have fewer surface area and hence less induced dipole-dipole interactions
73
Q

Are alkanes soluble in water? Why?

A

Insoluble because hydrogen bonds in water are stronger than alkanes’ London forces of attraction

74
Q

What kind of intermolecular forces do alcohols have? Why?

A

Hydrogen bonding, due to the electronegativity difference in the OH bond

75
Q

How do alcohols’ melting point and boiling point compare to other hydrocarbons’ of similar C chain-lengths? Why?

A

Higher, because they have hydrogen bonding (strongest type of intermolecular force) => Stronger than London forces

76
Q

Are alcohols soluble in water? Why does solubility depend on chain length?

A
  • Soluble when short chain- OH hydrogen bonds to hydrogen bond in water
  • Insoluble when long chain- non-polarity of C-H bond takes precedence
77
Q

Explain the trend of boiling temperatures of hydrogen halides HF to HI

A

-There is a general increase of boiling point from HCl to HI which is caused by increasing London forces because increasing number of electrons
- There is a big drop in boiling point from HF to HCL because fluorine is very electronegative therefore the hydrogen bonding is much stronger

78
Q

In what types of substances can hydrogen bonding happen?

A

any molecule which has a hydrogen atom directly to an oxygen or a nitrogen

79
Q
A

CHEMISTRY (11 decks)

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