1How many stable oxidation states do P-block elements normally exhibit?
2
2What are the 2 stable oxidation states formed by P-block elements?
Their group number, and their group number minus 2
3What affects the stability of P-block oxidation states?
The inert pair effect and octet expansion
4What is the inert pair effect?
The tendency of the s2 electron to not become hybridised to form an sp3 hybrid further down the group.
5Explain the inert pair effect
The hybridisation of orbitals requires an input of energy, which much be compensated for by the formation of additional bonds. The weaker bonds further down the group don't compensate for the energy input, and so hybridisation doesn't occur.
6What is octet expansion?
The ability of some atoms to use d-orbitals to form more than 4 covalent bonds
7How can octet expanded atoms be described?
Hypervalent
8Name 2 examples of hypervalent compounds
Potassium pentachloride and sulphur hexafluoride
9Describe the trend in metallic character across the P-block
Metallic character increases to the left and down the group due to the changes in ionisation energy
10What is amphotericity?
The ability of a reagent to act as both an acid and a base.
11Describe the character of metal oxides and hydroxides
Basic
12Describe the character of non-metal oxides and hydroxides
Acidic
13Name 2 P-block elements which exhibit amphoteric behaviour
Aluminium and Lead
14Describe the reaction of aluminium oxide and hydroxide with acids and alkalis.
Aluminium compounds will react with dilute acid to form salt solutions, and with sodium or potassium hydroxide to form aluminium hydroxide first, and then the aluminate ion [Al(OH)₄]⁻
15Describe the reaction of lead oxide and hydroxide with acids and alkalis.
Lead compounds will react with dilute acid to form salt solutions, and with sodium or potassium hydroxide to form lead hydroxide first, and then the plumbate ion [Pb(OH)₄]⁻
16Describe the character of boron
A non-metallic element that only forms covalent bonds
17Describe the character of aluminium
A metallic element with amphoteric behaviour which can form both covalent and ionic bonds
18Describe the nature of boron trifluoride and boron trichloride
Electron deficient
19What is a donor-acceptor compound?
A compound made of an electron deficient compound coordinately bonded to a species with a lone pair of electrons
20What are the similarities between boron nitride and elemental carbon
-They are both isoelectronic (A BN unit has the same number of electrons as a C₂ unit)
-Isomorphic
21Compare the structures and uses of graphene and hexagonal boron nitride
-Both form loosely bound hexagonal sheets
-Graphite sheets are out of register, whereas BN is in register
-BN bonds are polar
-BN has no delocalised electrons and so is an insulator.
-Both used as a lubricant
22Compare the structures and uses of diamond and cubic boron nitride
-Both are very hard and have high melting points
-BN is more chemically resistant than diamond
-Isostructural
-BN has 2 different types of atom involved whereas diamond only has 1
23What is the structure of aluminium oxide?
Ionic lattice
24What is the more stable oxidation state of tin?
+4
25Describe the nature of carbon monoxide
Unstable and strongly reducing
26Describe the nature of lead IV compounds
Strongly oxidising
27What are the characteristics of carbon dioxide?
Covalent colourless gas. Disolves in solution to form an acidic solution containing H₂CO₃
28What is an industrial use of carbon monoxide
The reduction of iron and copper oxides to their pure elemental states in blast furnaces
29Describe the nature of lead oxide IV
Strongly oxidising and easily reduced
30Describe the reaction between CO₂ and alkali solutions
If the alkali is in excess, sodium carbonate is formed. If the CO₂ is in excess, the hydrogen carbonate is formed
31What are the only common soluble lead compounds?
Lead (ii) nitrate, lead (ii) ethanoate, and lead (ii) chloride in hot water
32How can lead be tested for?
The addition of iodide ions. A bright, canary yellow precipitate (PbI₂) denotes the presence of lead.
33Why does silicon tetrachloride react with water wheras carbon tetrachloride (tetrachloromethane) doesn't?
Silicon tetrachloride has vacant d-orbitals which may be used to initiate the reaction, whereas tetrachloromethane doesn't.
34Give the equation for the reaction of silicon tetrachloride with water
$SiCl_4 + 2H_2O \rightarrow SiO_2 + 4HCl$
35What are the observations for the addition of concentrated sulphuric acid to a solution of Chloride ions?
White steamy fumes of hydrochloric gas are produced.
36What is the equation for the reaction between sodium chloride and concentrated sulphuric acid?
NaCl + H₂SO₄ → NaHSO₄ + HCl
37What are the observations for the addition of concentrated sulphuric acid to a solution of bromide ions?
White steamy fumes of hydrobromic gas are produced, then orange bromine vapour and colourless hydrogen bubbles. An eggy smell may be observed
38What are the equations for the reaction between sodium bromide and concentrated sulphuric acid?
NaBr + H₂SO₄ → NaHSO₄ + HBr
2HBr + H₂SO₄ → SO₂ + Br₂ + 2H₂O
39What are the observations for the addition of concentrated sulphuric acid to a solution of iodide ions?
White steamy fumes of hydroiodic gas are produced, then purple iodine vapour and colourless hydrogen bubbles, then the formation of a yellow solid from the further reduction of H₂SO₄. An eggy smell may be observed
40What are the equations for the reaction between sodium iodide and concentrated sulphuric acid?
NaI + H₂SO₄ → NaHSO₄ + HI
2HI + H₂SO₄ → SO₂ + I₂ + 2H₂O
41Why can iodide and bromide further react with H₂SO₄ whereas chloride cannot
Chloride ions are much stronger oxidising agents than iodide and bromide
42Give the equation for the reduction of PbO₂ with HCl (an example of lead acting as a base)
PbO₂ + 4HCl → PbCl₂ + Cl₂ + H₂O
43Give the equation for the reaction between lead oxide ii and sodium hydroxide (an example of lead acting as an acid)
PbO + 2NaOH → Na₂[Pb(OH)₄] (sodium plumbate)
44Give an equation in which carbon monoxide acts as a reducing agent
3CO + Fe₂O₃ → 2Fe + 3CO₂
45What is the equation for the reaction of chlorine with cold aqueous sodium hydroxide?
Cl₂ + 2NaOH → NaCl +NaClO + H₂O
46What is the equation for the reaction of chlorine with hot aqueous sodium hydroxide?
3Cl₂ + 6NaOH → 5NaCl +NaClO₃ + 3H₂O
47What type of reaction is the formation of bleach (NaClO and NaClO₃)?
Disproportionation
48What is observed when tetrachloromethane is added to water
The formation of 2 distinct layers as the substances are immiscible
49What is observed when silicone(iv) chloride is added to water
A white precipitate of SiO₂ and steamy fumes of HCl