10. CHEMICAL PERIODICITY Flashcards
1
Q
Colour of flame when Na reacts with O2
A
yellow
2
Q
Colour of flame when Mg reacts with O2
A
white
3
Q
Product formed when Na reacts with O2
A
white solid Na2O
white solid Na2O2
4
Q
Product formed when Mg reacts with O2
A
white solid MgO
5
Q
Reaction of Na with O2
A
- vigorous reaction
- produces white solid Na2O only
6
Q
Reaction of Mg with O2
A
- vigorous reaction
- produces white solid MgO only
7
Q
Product of reaction of Si with O2
A
SiO2
8
Q
Colour of flame when Si reacts with O2
A
pale blue flame
9
Q
Reaction speed of Si with O2
A
slow
10
Q
Reaction speed of P with O2
A
vigorous
11
Q
Product of reaction of P with O2
A
P4O10 and P4O6
12
Q
Colour of flame when P reacts with O2
A
white or yellow flame
13
Q
Observation when P reacts with O2
A
- white or yellow flame
- clouds of white P4O10 formed
14
Q
Colour of flame when S reacts with O2
A
blue flame
15
Q
Product when S reacts with O2
A
colourless fumes of SO2
16
Q
Reaction speed when S reacts with O2
A
gentle reaction
17
Q
Colour of flame when powdered Al reacts with O2
A
white
18
Q
Product of reaction when Al reacts with O2
A
Al2O3
19
Q
Reaction of Cl2 with O2
A
- does not react directly
- has several oxides
20
Q
Product of reaction of Na with Cl2
A
solid NaCl
21
Q
Product of reaction of Mg with Cl2
A
solid MgCl2
22
Q
Product of reaction of Al with Cl2
A
solid Al2Cl6
23
Q
Product of reaction of Si with Cl2
A
colourless volatile liquid SiCl4 (not giant structure)
24
Q
Product of reaction of P4 with Cl2
A
- liquid PCl5 in excess chlorine
- PCl3 in less chlorine
- PCl4 has an expanded octet
25
Chlorides of sulfur
SCl2 and S2Cl2
26
Observation when Na reacts with Cl2
- yellow flame
| - white solid produced
27
Observation when Mg reacts with Cl2
- white flame
| - white solid produced
28
When does Al2Cl6 exist
at low temperatures
29
When does AlCl3 exist
at high temperatures
30
Types of phosphorus
- white phosphorus (P4)
| - red phosphorus (P)
31
Observations when Na reacts with H2O
- vigorous reaction
- floats
- melts
- moves in circles
- white solid disappears
- gas produced
32
Product when Na reacts with H2O
alkaline solution of pH 14 NaOH and H2 gas
33
Product when Mg reacts with liquid H2O
weakly alkaline solution of pH 11 Mg(OH)2 and H2 gas
| - slow reaction
34
Why is Na(OH) more alkaline than Mg(OH)2
- magnesium hydroxide is only slightly soluble in water while sodium hydroxide is completely soluble in water
- a lower concentration of OH- ions enter the solution
35
Product when Mg reacts with steam
MgO and H2
| - vigorous reaction
36
Why do all Period 3 elements exist in positive oxidation states in their oxides
because oxygen is more electronegative than any of the Period 3 elements
37
Why are MgO and Mg(OH)2 used in indigestion remedies
they neutralise excess acid in the stomach
38
Reactions of Al2O3
ACID
- forms aluminium sulfate Al2(SO4)3
HOT CONCENTRATED ALKALI
- forms sodium tetrahydroxoaluminate NaAl(OH)4
39
Reaction of SiO2
HOT CONCENTRATED ALKALI
- forms Na2SiO3 (sodium silicate)
behaves as an acidic salt
40
Why does SiO2 not react with water
water cannot break down its giant molecular structure
41
Reaction of P4O10 with water
forms acidic solution of H3PO4 (phosphoric acid)
42
Reaction of SO2 and SO3 with water
SO2 --> H2SO2 (sulfurous acid)
| SO3 --> H2SO4 (sulfuric acid)
43
What happens to the electronegativity going across a period
increases
44
Why does electronegativity increase across a period
- the electrons are more strongly attracted to the nucleus
| - by the increasing positive nuclear charge
45
When does ionic bonding happen
the greater the difference in the electronegativity of the atoms, the more likely it is that the compound will have ionic bonding
46
Use of magnesium oxide
used to line the inside of furnaces
47
Use of Al2O3 and SiO2
- make ceramics
| - provide electrical insulation
48
How do the oxides of sodium and magnesium form alkaline solutions in water
the O2- turns into (OH)- by acting like a base and accepting a proton from H+
49
What happens when NaCl is added to water
- polar water molecules are attracted to the ions
- so dissolve the chlorides by breaking down the giant ionic structure
- solution formed contains Na+ and Cl- ions surrounded by water molecules (hydrated ions)
50
Products of reaction of SiCl4 with H2O
SiO2 and HCl gas
- SiO2 does not react with water (off-white precipitate)
- some of the HCl dissolves in water, leaving an acidic solution
51
Observations when SiCl4 reacts with H2O
- white fumes of HCl produced
| - off-white precipitate of SiO2
52
Name of reaction of SiCl4 and PCl5 with water
Hydrolysis
53
Products of reaction of PCl5 with water
- acidic solution of H3PO4
| - HCl gas. some of the gas dissolves to give an acidic solution
54
Observations when PCl5 reacts with H2O
- white fumes of HCl gas
55
General observations of NaCl and MgCl2 with water
- white solid dissolves to form less colour
| - alkaline solution produced
56
General observations of Al to S chlorides with water
- white fumes of HCl produced
| - acidic solution formed
57
How does Al2Cl6 form a solution with pH 3
- when added to water, the dimers are broken down and Al and Cl ions enter the solution
- the Al3+ causes a water atom surrounding it to lose an H+ ion, thus turning the solution acidic
58
What provides evidence for the ionic and covalent bonding of Al2O3
it reacts with both acids (which is typical of ionic oxides) and alkalis (which is typical of covalent oxides)
59
Observations when phosphorus reacts with chlorine
- green colour of chlorine disappears
- white flame
- white solid formed
- solid melts
60
What is the name of H3PO4
phosphoric(v) acid
61
What is the name of K2Cr2O7
potassium dichromate(VII)
62
What is the name of KMnO4
potassium manganate(VII)
63
Physical properties of ceramics such as aluminium oxide and silicon dioxide
- high melting/boiling/sublimation point
| - electrical/thermal insulator
64
Common brown gases
- bromine
| - NO2
