Topic 2 Bonding & Structure Flashcards

1
Q

What angle is linear?

A

180
No lone pair, furthest repel

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2
Q

What angle is V shape?

A

104.5
2 lone pairs

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3
Q

What angle is trigonal planar?

A

120
No lone pairs

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4
Q

What angle is trigonal pyramidal?

A

107
1 lone pair

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5
Q

What angle is tetrahedral?

A

109.5
No lone pairs

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6
Q

What angle is trigonal biphramidal?

A

5 bonds formed
90 in 2
120 in 3

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7
Q

What angle is hexagonal?

A

90 between every 2 bonds
6 bonds in total

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8
Q

What is an ionic bond?

A

Strong electrostatic attraction between opposite charged ions

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9
Q

What is the ionic attraction affected by?

A

Ionic radius (smaller=stronger)
Ionic charge (higher=stronger)

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10
Q

Qualities of ionic bonds

A

High mp
Soluble in water
Poor electron conductivity when solid but good when molten
Brittle

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11
Q

How are ionic bond qualities proven?

A

Electrolysis

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12
Q

What are covalent bonds? (2 marks)

A

Strong electrostatic attraction (1)
Between 2 nuclei and the share of pair of electrons (1)

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13
Q

What do σ bonds look like?

A

Overlap of s orbitals
2 O O overlapping
Or 1 s 1 p (O ∞ overlap)
Or ∞ ∞ overlap

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14
Q

What do π bonds look like?

A

8 8 overlap
2 p orbital overlapping sideways so 2 areas where electrons are shared

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15
Q

What is the definition of electronegativity?

A

Ability for an atom to attract bonding pair of electrons

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16
Q

What is a dative covalent bond?

A

Empty orbital of one atom overlap with an orbital with lone pair
(Donating a lone pair to an empty orbital)

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17
Q

What are examples of dative covalent bonds? Give 2

A

NH4+ (N donates to H)
Al2Cl6 (Cl donates to Al)

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18
Q

When u see mp/bp what do u think of?

A

London forces
PDPD
H bonds

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19
Q

Why can’t S form H bonds?

A

Not electronegative enough, much less electronegative than O
, doesn’t form very polar bonds like F O N

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20
Q

The structural feature that grapheme and graphite have in common is that the carbon atoms are arranged in…

A

Hexagonal rings within a layer

21
Q

What is the bond angle in BF3?

A

120

22
Q

What are the strongest interactions between molecules in solid boric acid? (H3BO3)

A

Hydrogen bonds

23
Q

How to find out the succession ionisation energies and their groups?

A

Biggest jump
Eg from 2 to 3 then it must be a G2 element

24
Q

How to determine isoelectronic ion size?

A

For atoms or ions that are isoelectronic, the number of protons determines the size. The greater the nuclear charge, the smaller the radius in a series of isoelectronic ions and atoms

25
Q

Ionic bonding is the strong electrostatic attraction between….

A

Cations and anions
(There are NO delocalised e-s in ionic bonds!)

26
Q

What does HCl exist at room temperature as?

A

Giant lattice of oppositely charged ions
(Gas)

27
Q

What are the bond angles within a layer of graphene and a layer of graphite?

A

All 120

28
Q

How is a dative covalent bond formed in NH3BF3?

A

Lone pair donated from N
BF3 accepts the lone pair and forms a full outer shell

29
Q

What’s the bond angle and name when there is a lone pair and 3 bonds?

A

107
Trigonal pyramidal

30
Q

What’s the bond angle and name when there are 4 bonds?

A

Tetrahedral
109.5

31
Q

Why is the mp of silicon(IV) dioxide way higher than iodine when both of them are covalent bonded?

A

Silicon oxide is a giant structure so contains many strong covalent bonds (1)
Iodine only has weak London forces (1)
More energy is needed to break silicon dioxide

32
Q

Why do both water and carbon dioxide have polar bonds but only water is a polar molecule? 4 marks

A

Oxygen is more electronegative than both H and C, so arrow points towards O
So polar bonds are formed, O is delta negative, C and H are delta positive
Water has V-shape, so vectors don’t cancel out
CO2 has linear shape, vectors cancel

33
Q

In terms of bonding and structure, why is the melting point of silicon way higher than chlorine when both are Period 3 elements?

A

Silicon: giant molecular, strong covalent bonds, lots of energy needed to break
Chlorine: simple molecular, diatomic and has weak London Forces

34
Q

Graphite vs graphene

A

Both hexagonal layer with C joined with 3 other C
London forces hold graphene layers together and make graphite
Unbonded Cs have delocalised electrons that are free to move

35
Q

Describe structure of diamond

A

Each C joined with 4 other C by covalent bonds
Regular Tetrahedral structure
No free electrons
Giant covalent lattice structure

36
Q

Why is lots of energy needed to break CaCO3?

A

Because of strong bonds within the carbonate ion

37
Q

Why is more energy required to break AlF than AlCl? (In terms of electronegativity) (6 marks)

A
  • larger electronegativity difference between Al and F than Al and Cl
  • AlCl mostly simple covalent
  • AlF more polar
  • AlCl more weaker London forces/intermolecular
  • AlF is giant structure, strong electrostatic attraction between ions
  • more energy needed to break stronger bonds
38
Q

What’s the only covalently bonded compound with a metal in it?

A

AlCl

39
Q

What’s the order of strength of bonds?

A

H bonds > PDPD > London

40
Q

Why is methanol and water ‘soluble in all proportions’?

A

Methanol forms H bonds with water
At least 1 lone pair on oxygen atom at 180 degrees

41
Q

What are 2 elements with special electronic configurations?

A

Copper and chromium

42
Q

What is it mean by hydrogen bonds? 2 marks

A

Hydrogen atom forming evident bond in the same or different molecule
With another atom that is more electronegative than H

43
Q

What is a metallic bond? 2 marks

A

Electrostatic attraction between metal cation and delocalised electrons (outer shell electrons)

44
Q

Why is magnesium a better electric conductor than sodium?

A

Mg is a smaller ion and has 1 extra delocalised electron than Na (group 2 vs group 1)

45
Q

Why is nitrogen much less reactive than carbon monoxide and hydrogen cyanide? (Given they are isoelectronic) (1 mark)

A

N has triple bonds with diatomic N, much stronger than C=O, C (triple) N, C-H
N2 also non polar, while the other two are polar

46
Q

Why is sodium chloride soluble in water? 3 marks

A
  • energy to overcome electrostatic attraction between sodium cation and chloride anion
  • lattice breaks down and ions are separated
  • energy supplied by hydration of ions by water molecules
47
Q

What structure is sodium chloride?

A

Lattice ionic structure

48
Q

What is it meant by a polar bond? How does polarity arise?

A
  • there is a charge separation between molecules of a bond , one is δ+ and one is δ-
  • when bond formation and one molecule is more electronegative than the other
  • electron cloud produce higher electron density towards electronegative element