Period 3 elements and thier oxides Flashcards
1
Q
What happens to the radius across the period?
A
Atomic radius decreases
2
Q
What happens to the first ionisation across the period?
A
First ionisation (generally) increases.
3
Q
What happens to the melting point across the period?
A
Melting points generally increase then decrease.
4
Q
What happens to the reactivity down group 2?
A
Group 2 increase in reactivity down the group.
5
Q
What happens to the reactivity down group 7?
A
Group 7 decrease in reactivity down the group.
6
Q
What is Acidified barium chloride used to test for?
A
Acidified barium chloride is used to test for sulfate ions, giving a white precipitate.
7
Q
What is Acidified silver nitrate used to test for?
A
Acidified silver nitrate is used to test for halide ions a white precipitate for chloride, a cream for bromide and yellow for iodide.
8
Q
How does sodium react with water?
A
Sodium reacts vigorously with water.
9
Q
What happens with sodium reacts with water?
A
Observations it floats, moves on the surface, fizzes. Forms a silver ball and eventually disappears.
10
Q
Give the equation for the reaction of sodium and water.
A
2Na + 2H2O -> 2NaOH + H2
11
Q
Does sodium and water make an acidic or alkaline solution?
A
It forms an alkaline pH, the more sodium added the more alkaline.
12
Q
How does Magnesium react with water?
A
Magnesium reacts very slowly with water.
13
Q
Give the equation for the reaction of magnesium and water.
A
Mg + 2H2O -> Mg(OH)2+ H2
14
Q
Does magnesium and water make an acidic or alkaline solution?
A
It has a very slightly alkaline pH.
15
Q
How does magnesium react with steam?
A
It reacts vigorously with steam
16
Q
Give the equation for the reaction of magnesium and steam.
A
Mg + H20(g) -> MgO + H2O
17
Q
What would you see when magnesium burns?
A
Observations: The magnesium burns with a bright white light, white solid is formed (magnesium oxide)
18
Q
Describe the bonding in sodium oxide
A
Sodium oxide is an ionic, basic oxide
19
Q
Give the formula for sodium oxide
A
Its formula is Na2O
20
Q
Describe the appearance of sodium oxide
A
It is a white solid.
21
Q
Describe and explain the melting point of sodium oxide.
A
It has a high melting point due to its ionic lattice which has strong electrostatic forces of attraction which require lots of energy to break.
22
Q
How is sodium oxide formed?
A
It is formed from the reaction between sodium and oxygen.
23
Q
What do you see when sodium burns.
A
A yellow flame is observed and a white solid formed.
24
Q
What do you have to do to get sodium to burn?
A
This happens spontaneously in air.
25
What other product can also be formed when sodium reacts with oxygen?
Some sodium peroxide Na2O2 will also be formed which is highly reactive.
26
What happens when sodium oxide reacts with water?
Sodium oxide reacts with water to produce a colourless solution of sodium hydroxide.
27
Give the equation for the reaction of sodium oxide and water.
Na2O + H2O -> 2NaOH
28
How does sodium oxide react with acid.
It is a base so reacts with acid to form salt and water.
29
What happens when sodium oxide is placed into water?
In water the sodium oxide dissolves and the oxide ion acts a base and accepts H+ ions from water or acid.
30
Give the ionic equation for the reaction of oxide ions and water.
O2- + H2O ->2OH-
31
Give the ionic equation for the reaction of hydrogen ions and water.
O2- + 2H+ ->H2O
32
Describe the bonding in Magnesium oxide
Magnesium oxide is an ionic, basic oxide.
33
Give the formula for Magnesium oxide
Its formula is MgO
34
Describe the appearance of Magnesium oxide
It is a white solid.
35
Describe and explain the melting point of Magnesium oxide.
It has a high melting point due to its ionic lattice which has strong electrostatic forces of attraction which require lots of energy to break.
36
Why does magnesium oxide have a higher melting point that sodium oxide?
It’s melting point is higher than sodium oxide as it has a higher charge and a smaller radius than the sodium ion so the forces of attraction are stronger.
37
How is Magnesium oxide formed?
It is formed from the reaction between Magnesium and oxygen.
38
What do you see when Magnesium burns.
A white flame is observed and a white solid formed.
39
What happens when Magnesium oxide reacts with water?
Magnesium oxide is sparingly soluble in water but some does react to form magnesium hydroxide.
40
Give the equation for the reaction of sodium oxide and water.
MgO + H2O ->Mg(OH)2
41
What is the pH of magnesium hydroxide?
The pH is slightly alkaline with a pH of about 9.
42
How does magnesium oxide react with acid?
It is a base so reacts with acids to produce a salt and water.
43
Describe the structure and bonding in Silicon dioxide
Silicon dioxide is a covalent, acidic oxide.
44
Give the formula of silicon dioxide
Its formula is SiO2
45
Describe the appearance of silicon dioxide
It is a white powder.
46
Describe the structure and bonding in Silicon Dioxide
It is a covalent, macromolecular (giant covalent) structure.
47
Describe and explain the melting point of Silicon Dioxide.
It has a high melting point as it has lots of strong covalent bonds which need to be broken which takes a lot of energy.
48
What happens when Silicon dioxide reacts with oxygen?
Finley divided silicon reacts with oxygen when heated.
49
What happens when Silicon dioxide reacts with water?
It doesn’t react or dissolve in water.
50
What is the pH of Silicon dioxide?
It has a pH of 7.
51
How does Silicon dioxide react with bases?
It reacts with bases to form silicates SiO32-
52
How does Silicon dioxide react with sodium hydroxide?
It reacts with hot concentrated sodium hydroxide.
53
Give the ionic equation for the reaction of Silicon dioxide react sodium hydroxide?
SiO2 + 2OH- -> SiO32-+ H2O.
54
Describe the structure and bonding in Phosphorous (V) oxide
Phosphorous (V) oxide is a covalent, acidic oxide.
55
Give the formula of Phosphorous (V) oxide
Its molecular formula is P4O10
56
Describe the appearance of Phosphorous (V) oxide
It a white solid.
57
Describe the structure and bonding in Phosphorous (V) oxide
It is a covalent, molecular (simple covalent) structure.
58
Describe and explain the melting point of Phosphorous (V) oxide.
Its melting point is lower as less energy is needed to break the weaker intermolecular forces.
59
What happens when Phosphorous (V) oxide reacts with oxygen?
Phosphorous burns spontaneously in air with a very bright white flame and forms white smoke which is a combination of oxides. In excess oxygen you get almost all Phosphorous (V) oxide.
60
What happens when Phosphorous (V) oxide reacts with water?
It reacts with water to produce phosphoric (V) acid H3PO4.
61
What is the pH of Phosphorous (V) oxide?
Phosphorous oxide is an acidic oxide and reacts with bases forming phosphate salts with the ion PO43-.
62
Give the ionic equation for the reaction of Phosphorous (V) oxide with sodium hydroxide.
12OH- + P4O10 -> 4 PO43- + 6H2O.
63
Does Phosphorous (V) oxide react with acids or bases?
It reacts with basic oxides such as magnesium and sodium.
64
Give the equation for the reaction of Phosphorous (V) oxide with sodium oxide.
6Na2O + P4O10 -> 4Na3PO4
65
Give the equation for the reaction of Phosphorous (V) oxide with Magnesium oxide.
6MgO + P4O10 -> 2Mg3(PO4)2
66
How do basic oxides react with Phosphorous (V) oxide
Basic oxides also react with H3PO4. These form the same salts as above but also water.
67
What oxides does sulphur form?
Sulfur forms 2 oxides; sulfur (IV) oxide (sulfur dioxide) and sulfur (VI) oxide (sulfur trioxide).
68
What are the formulas of the oxides of sulphur?
The formulas are SO2 and SO3.
69
Describe the bonding and pH of the oxides of sulphur.
They are covalent, acidic oxides.
70
What is the structure and bonding in sulphur oxides?
They are covalent, molecular (simple covalent) structures.
71
Describe sulphur dioxide.
Sulfur dioxide is a colourless gas with a pungent odour.
72
Describe sulphur trioxide.
Sulfur trioxide is a colourless liquid.
73
Give the shape and bond angle in sulphur dioxide.
The SO2 molecule is bent due to the lone pair. (119o). It is polar.
74
Give the shape and bond angle in sulphur trioxide.
The SO3 molecule is trigonal planar. (120o). It is non polar as it’s symmetrical.
75
Describe how sulphur dioxide is formed and the observations you would make.
SO2 is formed from sulfur burning in air. The yellow sold sulfur melts to form a red liquid which burns with a blue flame forming misty fumes of a choking and pungent gas.
76
How is sulphur trioxide made and what conditions are needed?
SO2 can be converted to SO3 on reaction with more oxygen in the presence of a vanadium (V) oxide catalyst.
77
What happens when sulphur dioxide reacts with water?
SO2 reacts with water to produce sulphuric (IV) acid H2SO3 (NB formula is S3 NOT S4). It is also called sulfurous acid.
78
Give the pH of the resulting solution with sulphur dioxide reacts with water.
It is weakly acidic as it is reversible and the equilibrium lies to the left.
79
What happens when sulphur trioxide reacts with water?
SO3 reacts vigorously with water to produce sulfuric (VI) acid H2SO4
80
Do sulphur dioxide and sulphur trioxide react with acid or bases?
Both oxides of sulfur react with bases.
81
What ion is formed when sulphur dioxide reacts with bases?
Sulfur dioxide forms sulfate (IV) ions. SO32- (Sulfite ion)
82
What ion is formed when sulphur trioxide reacts with bases?
Sulfur trioxide forms suflate (VI) ions SO42-(Sulfate ion)
83
Give the equation for when sulphur dioxide reacts with bases.
SO2 + 2OH- -> SO32- + H2O
84
Give the equation for when sulphur trioxide reacts with bases.
SO3 + 2OH- -> SO42- + H2O
85
How is sulfuric (IV) acid formed?
When sulfur dioxide reacts is forms sulfuric (IV) acid H2SO3.
86
How does sulphur make 4 covalent bonds?
It promotes one electron into the 3d sub-shell to be able to form four covalent bonds. The sulfur atom has a lone pair of electrons.
87
Give the shape and bond angle of sulfuric (IV) acid
The shape is pyramidal (bond angle 107.5o).
88
What happens when the sulfuric (IV) acid donates hydrogen ions?
It can form 2 different anions as the H+ leaves.
89
How is sulfuric (VI) acid formed?
When sulfur trioxide reacts is forms sulfuric (VI) acid H2SO4.
90
How does sulphur make 6 covalent bonds?
It promotes two electrons into the 3d sub-shell to be able to form six covalent bonds.
91
Give the shape and bond angle of sulfuric (VI) acid
The shape is tetrahedral (bond angle 109.5o).
92
What happens when the sulfuric (VI) acid donates hydrogen ions?
It can form 2 different anions as the H+ leaves
93
What is Phosphoric acid used for?
Phosphoric acid is used in food and drink (e.g. Cola).
94
What is formed when Phosphoric acid reacts with water?
When P4O10 reacts with water is forms phosphoric (V) acid H3PO4.
95
How does Phosphoric acid make 5 covalent bonds?
The phosphorus atoms promote electrons into the 3d sub-shell to be able to form five covalent bonds.
96
Give the shape and bond angle of Phosphoric acid
It is tetrahedral 109.5o
97
How does Phosphoric acid act as an acid?
The hydrogen atoms are acidic hydrogen atoms as they are bonded to electronegative oxygen atoms and can donate H+ ions.
98
What happens when the Phosphoric acid donates hydrogen ions?
It can form 3 different anions as the H+ leave the molecule.
99
What happens to the melting points of the metal oxides?
For the metal oxides as the charge increases and the size decreases the melting point increases.
100
Why is the melting point of Aluminium oxide lower than magnesium oxide
Aluminium oxide is lower than magnesium oxide because it is so small and charged that it polarises the electrons in the oxide. As Aluminium Oxide has a degree of covalent character this weakens it and reduces the melting point.
101
Compare the melting point of P4O10 , SO2 and SO3
Why P4O10 has a higher melting point than SO2 and SO3
102
What types of bonding are there in P4O10 , SO2 and SO3
All 3 are simple molecular with covalent bonds.
103
Why has P4O10 got a higher melting point?
P4O10 has a higher melting point because it is a larger molecule with more electrons so the van der Waal’s forces between the molecules are greater so more energy is needed to break them.
104
Why has SO3 got a higher melting point than SO2?
SO3 is larger than SO2 so the melting point is higher for the same reasons even though SO2 is polar and SO3 isn’t.
105
What happens when the acidic oxides react with water?
When acidic oxides react with water they form oxyacids.
106
What are oxyacids?
Oxyacids are covalent compounds which form ions in water.
