Bonding Flashcards

1
Q

What is ionic bonding

A

Strong electrostatic forces of attraction between oppositely charged ions held in a lattice

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

Between MgO and NaCl which one is stronger/has a higher melting point

A

MgO is stronger/has a higher melting point than NaCl because when the ions are smaller and or have higher charges they have higher melting points and are stronger.

The ions involved in MgO are Mg2+ and O2+ where as in NaCl it is Na+ and Cl-

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

What effect does going down a group have on ionic radii

A

It increases because the ions have more shells of electrons

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

Why are positive ions smaller than negative ions

A

Positive ions are smaller because it has one less shell of electrons and the ratio of protons to electrons has increased so there is a greater net force on remaining electrons holding them more closely

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

Why do ionically bonded substances have high melting and boilling points

A

Requires alot of energy to break the strong electrostatic forces of attraction between opposites charged ions

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

Do ionic compounds conduct electricity? Why?

A

Yes, When molten/in solution as the ions are free to move and carry charge through the strcture

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

What is molecular covalent bonding

A

A shared pair of electrons that has Weak van der waals forces of attraction between molecules

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

Can molecular covalent molecules conduct electricity? why?

A

No- all electrons used in bonding and aren’t free to move

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

Do molecular covalent substances have a high/low melting and boiling point? why?

A

Low- Weak van der Waals forces of attraction between molecules that don’t take much energy to overcome

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

Why do macromolecular covalent bonds have high MP and BP

A

Requires lots of energy to overcome the many strong covalent bonds

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

Why do metallic compounds have high MP and BP

A

Strong forces of attraction between metal ions and negatively charged sea of delocalised electrons

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

Do macromolecular covalent bonds conduct electricity

A

Most don’t as all electrons are used in bonding

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

Why do metallic compounds conduct electricity

A

The delocalised electrons move throughout the metal and to carry charge

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

Define electronegativity

A

The ability of an atom to attract the pair of electrons in a covalent bond to itself

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

Examples of molecular covalent substances

A

Iodine
Ice
CO2
Water
Methane

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

What effects electronegativity (3)

A

The number of protons in the nucleus;
The distance from the nucleus;
The amount of screening by inner electrons

17
Q

Why exactly does the electronegativity increase?

A

Electronegativiity incrases across a period-Number of protons increases and atomic nucleus decreases because the eletrons in the same shell are pulled in more
It decreases down a group bcause the distance between the nucleaus and the outershell increases and the shielding of inner shell elctrons increases

18
Q

How do you get a non polar bond

A

Both bonding elements have the same electronegativities

19
Q

How do you get a polar bond

A

Bonding atoms have different electronegatuvities

20
Q

Define metallic bonding

A

The electrostatic force of attraction between the positive metal ions and the delocalised electrons

21
Q

What conditions are required for hydrogen bonding to occur?

A
  • Partial charge on H and F/N/O
  • Hydrogen attracted to the lone pair of O/N/F
  • Large Electrobegativity diff
22
Q

why is ice less dense than liquid water

A

Ice is less dense than water because the hydrogen bond orientation in ice causes the molecules to push farther apart, lowering the density.

23
Q

When is a dative/co-ordinate covalent bond formed

A

When an electron deficient atom/ion accepts a lone pair of electrons from an atom/ion with a lone pair of electrons

24
Q

what does the electron pair repulsion theory state

A

that electron pairs will take up positions as far away from each other as possible to minimise the repulsive forces between them

25
Q

Which experiences the most repulsion?
(Lone pair-Lone pair
Lone pair-Bond pair
Bond pair-Bond pair)

A

Lp-Lp strongest repulsion
Lp-Bp repulsion middle
Bp-Bp repulsion weakest

26
Q

Why are negative ions bigger than the corresponding atom

A

It has more electrons than the correspondng atom but the same number of protons so the pull of the nucelus is shared over more electrons and the attraction per electron is less making the ion bigger

27
Q

what are the main factors affecting the strength of Metallic bonding

A

Number of protons( the more protons the stronger the bond)
Number of delocalised electrons(more delocalised= stronger)
Size of ion(the smaller the ion the stronger the bond)

28
Q

Fact

A

A compound comtainning a small electronegatvity diff will be covalent
A compound containing elelmts of very diff electrongatvity and hence a very agre electronagtivity diff (>1.7) will be ionic

29
Q

When does a dipole dipole occur

A

When the elements in the bond have diff electronegativities around 0.3 to 1.7

30
Q

Symmetrical molecules

A

A symmetrical molecule (all bonds identical and NO lone pairs) will not be polar even if individual bonds wothin the molecule are polar

31
Q

Why are symmetrica; molecules non polar

A

The individual dipoles on the bonds cancel out due to symmetrical shape of the molecule

32
Q

What is the main factor affecting size of Van der Waals forces

A

The more electrons there are in the molecule the more VDW forces

33
Q

Poperties of Dipole Dipole

A

Occur between polar molecules
Stronger than VDW
Assymetrical

34
Q

Hydrogen bonding

A

A hydrogen attacthed to the three most electronegative compounds NFO and must have an available pair of lone electrons
U draw the line from the h bond to the lone pair

35
Q

which atoms are the most electronegative

A

F N O CL

36
Q

What is a polar molecule

A

When there is an electronegatibity diff between two or more atoms in a molecule

37
Q

How can the shape of a molecule have an effect on the size of VDW forces

A

Long staright chains have a large surface area so they have stronger VDW whilst chains with kinks have a lower surface area

38
Q

What are common compounds with dipole dipole

A

C-Cl C-Br C-F H-CL C=O

39
Q

What are the 4 types of Crystals

A

Macromolecular
Giant Ionic
Molecular
Metallic