Brainscape's Knowledge GenomeTM

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


See full index

1. Physical Chemistry > 1.3 Bonding > Flashcards

1.3 Bonding Flashcards

1
Q

What is an ionic bond and what does it occur between

A
  • Occurs between metals and non-metals.
  • Electrons are transferred from the metal to the non-metal to achieve a full outer shell (the electron configuration of a noble gas).
  • This creates charged particles called ions.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of forces are present in an giant ionic lattice

A

Oppositely charged ions attract through electrostatic forces of attraction.

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

What do covalent bonds occur between

A

2 non-metals.

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

What is a covalent bond

A
  • Electrons are shared between the two outer shells in order to achieve a full outer shell.
  • Multiple electron pairs can be shared to produce multiple covalent bonds.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a simple molecular structure

A

Consist of covalently bonded molecules held together with weak van der waals forces.

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

What is a macromolecular structure

A

Structures that are covalently bonded into a giant lattice structure.

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

How are dative/ coordinate covalent bonds formed

A
  • When electrons in a shared pair are supplied from a single atom.
  • Indicated by an arrow from the lone electron pair.
  • E.g. Ammonia (NH3) has a lone pair of electrons that can form a dative bond with a H+ ion to produce an ammonium ion (NH4+).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a metallic bond

A
  • Consists of a lattice of positively charged ions surrounded by a ‘sea’ of delocalised electrons.
  • This produces very strong electrostatic forces of attraction between the positively charged metal ions and delocalised electrons.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the charge on the metal ion affect the strength of the electrostatic forces

A

The greater the charge on the metal ion, the stronger the electrostatic forces of attraction as more electrons are released into the ‘sea’.

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

How does the size of the atom affect the strength of the electrostatic forces

A

Larger ions produce a weaker attraction due to their greater atomic radius which means there is a weaker attraction between the nucleus and delocalised electrons as they are further away.

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

What are physical properties

A
  • Boiling point
  • Melting point
  • Solubility
  • Conductivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 4 main types of crystal structure

A
  • Ionic
  • Metallic
  • Simple molecular
  • Macromolecular
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are properties of giant ionic lattices

A
  • High melting and boiling points.
  • Generally soluble in water.
  • Do not conduct electricity in the solid state.
  • Conduct electricity when molten or in solution.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why do ionic substances have high melting and boiling points

A

There are strong electrostatic forces of attraction holding the ionic lattice together, so lots of energy is required to overcome them.

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

Why do ionic substances conduct electricity when molten or in solution

A
  • In this state, the ions separate and are no longer held in a lattice.
  • They are therefore free to move and carry a flow of charge (an electrical current).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are properties of giant metallic structures

A
  • Good conductors
  • Malleable
  • High melting and boiling points (often solid at room temperature)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why are metals good conductors

A

The ‘sea’ of delocalised electrons is able to move and carry a flow of charge.

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

Why are metals malleable

A

The layers of positive ions are able to slide over each other and the delocalised electrons prevent fragmentation as they can move around the lattice.

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

Why do metals have high melting and boiling points

A

The electrostatic forces of attraction between the positive ions and delocalised electrons are very strong, so a lot of energy is required to overcome them.

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

What are properties of simple molecular structures

A
  • Low melting and boiling points
  • Generally insoluble in water
  • Do not conduct electricity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why do simple molecules have low melting and boiling points

A

They have van der waals forces between molecules which are very weak, so not much energy is required to overcome them.

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

Why can’t simple molecules conduct electricity

A

Their structures contain no charged particles.

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

Why do macromolecular structures have very high melting points

A

Each atom has multiple covalent bonds which are very strong.

24
Q

Describe the structure of diamond and properties

A
  • Made up of carbon atoms each bonded to 4 other carbon atoms, making it very strong.
  • It has a high melting and boiling point, insoluble in water and doesn’t conduct electricity.
25
Q

Describe the structure of graphite and some properties

A
  • Each carbon atom is bonded to 3 others in flat sheets.
  • The electrons not used in bonding (1 free as carbon has a valency of 4) are released as free electrons which move between layers, so it can conduct electricity.
  • It also has a high melting and boiling point, insoluble in water and can conduct electricity.
26
Q

What is the shape of a molecule determined by

A
  • The number of electron pairs around the central atom.
  • Each electron pair naturally repels each other so that the largest bond angle possible exists between the 2 covalent bonds.
27
Q

How do lone pairs of electrons affect the bond angles and why

A
  • Lone pairs provide additional repulsive forces which reduce the size of the bond angles.
28
Q

By how much do lone pairs reduce bond angles by

A

2.5 degrees

29
Q

What is the shape of a molecule with 2 bonding pairs of electrons and 0 lone pairs

A

Linear (e.g. BeCl2)

30
Q

What is the size of the bond angle in a linear molecule

A

180 degrees

31
Q

What is the shape of a molecule with 2 bonding pairs of electrons and 2 lone pairs

A

V - shaped (e.g. H2O)

32
Q

What is the size of the bonding angle in a v-shaped molecule

A

104.5 degrees

33
Q

What is the shape of a molecule with 3 bonding pairs of electrons and 0 lone pairs

A

Trigonal planar (e.g. BF3)

34
Q

What is the size of the bonding angle in a trigonal planar molecule

A

120 degrees

35
Q

What is the shape of a molecule with 3 bonding pairs of electrons and 1 lone pairs

A

Triangular Pyramid (e.g. NH3)

36
Q

What is the bonding angle in a triangular pyramid molecule

A

107 degrees

37
Q

What is the shape of a molecule with 4 bonding pairs of electrons and 0 lone pairs

A

Tetrahedral (e.g. CH4)

38
Q

What is the bonding angle in a tetrahedral molecule

A

109.5 degrees

39
Q

What is the shape of a molecule with 5 bonding pairs of electrons and 0 lone pairs

A

Trigonal Bipyramid (e.g. PF5)

40
Q

What are the bonding angles in a trigonal bipyramid molecule

A

90 and 120 degrees

41
Q

What is the shape of a molecule with 6 bonding pairs of electrons and 0 lone pairs

A

Octahedral (e.g. SF6)

42
Q

What is the bonding angle in an octahedral molecule

A

90 degrees

43
Q

What is electronegativity

A

The power of an atom to attract the pair of electrons in a covalent bond.

44
Q

What are 3 factors that affect electronegativity

A
  • Nuclear charge
  • Atomic radius
  • Shielding
45
Q

How does nuclear charge affect electronegativity

A

A greater nuclear charge will increase the electronegativity of an atom as there will be a stronger attraction between the nucleus and shared pair of electrons.

46
Q

How does the size of the atomic radius affect electronegativity

A
  • A smaller atomic radius means there is a shorter distance between the nucleus and shared pair of electrons, causing a stronger attraction.
  • This is why electronegativity increases along a period and decreases down a group as shielding increases.
47
Q

When do non-polar covalent bonds occur

A

When the 2 atoms in a covalent bond have the same/very little difference in electronegativity.
- This means that the pair(s) electrons in the covalent bond are shared equally.

48
Q

When do polar covalent bonds occur

A
  • When the 2 atoms in a covalent bond have different electronegtivities.
  • This means that the pair(s) of electrons are not shared equally and the more electronegative element has a greater share of them.
49
Q

What is a permanent dipole

A
  • A polar bond is formed when there is a difference in electronegativities.
  • The more electronegative atom draws the pair(s) of electrons towards itself and away from the other atom, producing delta positive and delta negative regions in the molecule.
  • This is a permanent dipole.
50
Q

What is an induced dipole

A

Can form when the electron orbitals around a molecule are influenced by another charged particle.

51
Q

What are the 3 main types of intermolecular forces in order of strength (from weakest to strongest)

A
  1. Van der Waals forces
  2. Permanent dipole
  3. Hydrogen bonding
52
Q

What are Van der Waals forces

A
  • Random movement of electrons causes a temporary dipole.
  • This causes an induced dipole in a nearby molecule.
  • The opposite dipoles in each molecule are attracted by van der waals forces.
53
Q

How is the strength of van der waals forces affected

A
  • Molecules with larger Mr values experience stronger van der waals forces as there are more electrons in the molecule.
  • Straight chain molecules experience stronger van der waals forces than branched molecules as they can pack closer together which reduces the distance over which the forces act.
54
Q

What are permanent dipole-dipole forces

A
  • Act between molecules with a polar bond.
  • The partially positive end of one molecule attracts the partially negative end of another molecule which holds the molecules together in a lattice-like structure.
55
Q

What atoms are needed for hydrogen bonding to occur and why

A
  • Nitrogen, Oxygen and Fluorine.
  • The H in the covalent bond between these atoms is very polarised as there is a large difference in electronegativity.
  • This makes H bonds the strongest type of intermolecular force.
56
Q

What is a hydrogen bond

A
  • When the lone pair on a F/O/N atom forms a bond with a hydrogen atom also bonded to a F/O/N atom.
  • This is shown with a dotted line.
57
Q

What are properties of hydrogen bonded molecules

A

They have much higher melting and boiling points compared to other molecules of similar size.

1. Physical Chemistry (5 decks)

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