Brainscape's Knowledge GenomeTM

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


See full index

Chemistry > Bonding > Flashcards

Bonding 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 is ionic bonding?

A

The strong electrostatic force of attraction between oppositely charged ions formed by electron transfer

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

How are cations formed?

A

Metals lose electrons from their valence shell forming positively charged cations

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

How are anions formed?

A

Non-metal atoms gain electrons forming negatively charged anions

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

When is the ionic bonding stronger and when are the melting points higher?

A

When the ions are smaller and/or have higher charges
e.g. MgO has higher m.p. than NaCl as Mg is 2+ and Na is +

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

Why are positive ions smaller compared to their atoms?

A
  • It has one less shell of electrons - The ratio of protons to electrons has increased
  • So there is a greater net force on the remaining electrons holding them more closely
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why are negative ions from groups 5-7 larger than their corresponding atoms?

A
  • The negative ions have more electrons than the atom
  • But it has the same number of protons
  • So the pull of the nucleus is shared over more electrons and the attraction per electron is less, making the ion bigger
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which predictable patterns do ionic radii show?

A
  • Ionic radii increase with increasing negative charge
  • Ionic radii decrease with increasing positive charge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give an example of the patterns of ionic radii

A
  • N3-, O2-, F- and Na+, Mg2+, Al3+ all have the same electronic structure
  • There are increasing numbers of protons from N to F and then Na to Al but the same number of electrons
  • The effective nuclear attraction therefore increases and ions get smaller
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the trend of ionic radii in a group?

A

The size increases down the group. As one goes down the group, the ions have more shells of electrons so distance increases

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

What kind of structure do ionic compounds form?

A

Giant ionic lattice (crystal structures)

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

What is the attraction like when ionic compounds are formed?

A

The attraction between the ions happens in all directions
Overall the lattice is electrically neutral as the positive charges cancel out the negative charges

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

What does the type of ionic lattice formed depend on?

A

The size of the positive ions and negative ions which are arranged in an alternating fashion
e.g. ionic lattice of MgO and NaCl are cubic

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

What state are most ionic compounds in at room temp?

A

Solid

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

Why are most ionic compounds solid at room temp?

A

There is not enough energy to overcome the strong electrostatic forces of attraction between the oppositely charged ions
(So ionic compounds have high m.p. and b.p.)

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

When are melting and boiling points also higher in ionic lattices?

A

They are higher for lattices that contain ions with a greater ionic charge (there is a stronger attraction between the ions)

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

What must there be for electrical current to flow?

A

Present, freely moving, charged particles such as electrons or ions

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

What will many ionic compounds dissolve in?

A

Polar solvents e.g. water

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

What 2 main factors is solubility dependent on?

A
  • Breaking down the ionic lattice
  • The polar molecules attracting and surrounding the ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do polar molecules affect ionic lattices?

A

They can break down and disrupt the ionic lattice and surround each ion in solution
- The + end of the polar molecule can surround the negative anion
- The - end of the polar molecule can surround the positive cation

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

What does the solubility of an ionic compound depend on?

A

The relative strength of the electrostatic forces of attraction within the ionic lattice and the attractions between the ions and the polar molecules

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

What is the connection between ionic charge and solubility of a compound?

A

In general, the greater the ionic charge the less soluble an ionic compound is
(there are many exceptions though)

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

What gives evidence for the existence of ions?

A

The behaviour of ionic substances during electrolysis

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

Why does electrolysis give evidence for the existence of ions?

A
  • Positive ions in solution are attracted to the negative electrode
  • Negative ions in solution are attracted to the positive electrode
24
Q

What is a covalent bond?

A

A covalent bond involves the electrostatic attraction between nuclei of 2 atoms and the bonding electrons of their outer shells

25
Q

What are lone pairs?

A

Non-bonded pairs

26
Q

What is dative covalent bonding?

A

Some molecules have a lone pair of electrons that can be donated to form a bond with an electron deficient atom

27
Q

What is an electron deficient atom?

A

An atom that has an unfilled outer orbital

28
Q

Are both electrons from the same atom in dative covalent bonding?

A

Yes

29
Q

What is dative covalent bonding also known as?

A

Coordinate bonding

30
Q

What happens in an ammonium ion?

A
  • The hydrogen ion H+ has space for 2 electrons
  • The nitrogen atom in ammonia has a lone pair of electrons which it can donate to the hydrogen ion to form a dative covalent bond
31
Q

What does ammonium chloride exist as at high temperatures?

A
  • As a monomer (AlCl3)
  • The molecule is electron deficient and needs 2 electrons to complete the aluminium atom’s outer shell
32
Q

What happens to aluminium chloride at lower temperatures?

A
  • The 2 molecules of AlCl3 join together to form a dimer (Al2Cl6)
  • The molecules combine because lone pairs of electrons on 2 of the chlorine atoms form 2 coordinate bonds with the aluminium atoms
33
Q

What is the bond energy?

A

The energy required to break one mole of a particular covalent bond in the gaseous states (its units are kjmol^-1)

34
Q

What does a larger bond energy mean?

A

The stronger the covalent bond

35
Q

What is bond length?

A

The internuclear distance of 2 covalently bonded atoms (the distance from the nucleus of 1 atom to another atom which forms the covalent bond)

36
Q

What does a greater force of attraction between the electrons and nuclei mean?

A
  • The more the atoms are pulled closer to each other
  • This decreases the bond length of a molecule and increases the strength of the covalent bond
37
Q

Which are the shortest and strongest covalent bonds?

A

Triple bonds

38
Q

Why are triple bonds the shortest and strongest covalent bonds?

A
  • Due to the large electron density between the nuclei of the 2 atoms
  • This increases the forces of attraction between the electrons and nuclei of the atoms
  • As a result of this, the atoms are pulled closer together causing a shorter bond length
  • The increased forces of attraction also means the covalent bond is stronger
39
Q

What is the theory for valence electrons?

A

The valence shell electron pair repulsion theory (VSEPR)

40
Q

What is VSEPR?

A

It predicts the shape and bond angles of molecules

41
Q

What happens because electrons are negatively charged?

A

They will repel other electrons when close to each other

42
Q

What happens in a molecule with bonded pairs of electrons?

A

The bonding pairs of electrons will repel other electrons around the central atom forcing the molecule to adopt a shape in which these repulsive forces are minimised

43
Q

When determining the shape and bond angles of a molecule, what VSEPR rules need to be followed?

A
  • Valence shell electrons are found in the outer shell
  • Electron pairs repel each other as they have the same charge
  • Lone pair electrons repel each other more than bonded pairs
  • Repulsion between multiple and single bonds is treated the same as repulsion between single bonds
  • Repulsion between pairs of double bonds are greater
  • The most stable shape is adopted to minimise the repulsion forces
44
Q

How do lone pairs of electrons affect the shape and bond angles?

A
  • They have a more concentrated electron charge cloud than bonding pairs of electrons
  • The cloud charges are wider and closer to the central atom’s nucleus
  • The order of repulsion is lone pair-lone pair >lone pair-bond pair>bond pair-bond pair
45
Q

How many degrees is in a linear shape?

A

180 e.g. CO2

46
Q

How many degrees is in a trigonal planar?

A
  1. e.g. BF3
47
Q

How many degrees is in a non-linear?

A

104.5 e.g. H2O

48
Q

How many degrees is in a trigonal pyramidal?

A

107 e.g. NH3

49
Q

How many degrees is in a tetrahedral?

A

109.5 e.g. CH4

50
Q

How many degrees is in a triganol bipyramidal?

A

90 and 120 e.g. PF5

51
Q

How many degrees is in an octahedral?

A

90 e.g. SF6

52
Q

How are metal atoms arranged?

A

They are tightly packed together in a lattice structure
They are often packed in hexagonal layers or in a cubic arrangement

53
Q

What happens to the electrons when the metal atoms are in lattice structures?

A
  • The electrons in their outer shells are free to move throughout the structure
  • They are called delocalised electrons and they are not bound to their atom
54
Q

What happens when the electrons are delocalised?

A

The metal atoms become positively charged ions

55
Q

How is the neatly arranged lattice in a metal kept in place?

A

The positive charges repel each other

56
Q

What kind of forces are there in a metal lattice?

A

There are very strong forces between the positive metal centres and the ‘sea’ of delocalised electrons

Chemistry (6 decks)

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