2.4 Period 3 Flashcards Preview

AQA A-Level Inorganic Chemistry > 2.4 Period 3 > Flashcards

Flashcards in 2.4 Period 3 Deck (22)
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1

What are the types of each element in period 3?

Sodium, magnesium and aluminium = metallic

Silicon = metalloid

Phosphorus, sulfur and chlorine = non-metals

Argon = Nobel gas

2

Which elements do we need to know that react with water?

Sodium and magnesium

3

Information about reaction between sodium and water?

Sodium reacts ionically to form a 1+ positive ion

2Na + 2H2O -> 2NaOH + H2

This reaction is vigorous - fizzes rapidly
Less energy is required to ionise sodium (than Mg) therefore sodium is more reactive

4

Information about reaction between magnesium and water?

Magnesium reacts ionically to form a 2+ positive ion

Mg + 2H2O -> Mg(OH)2 + H2

This reaction is slow

5

How can we change the speed of the magnesium + water reaction?

By using steam instead of water provides greater energy resulting in a violent reaction

Mg + H2O(g) -> MgO(s) + H2

Magnesium burns with a bright white flame

6

How do we react period 3 elements with oxygen?

Using a gas jar containing oxygen
The combustion spoon (with the sample) is placed inside the jar after being heated

7

What are the products of period 3 elements and oxygen?

Na2O
MgO
Al2O3
SiO2
P4O10
SO2
SO3

8

Information about sodium and oxygen?

Sodium is stored under oil to stop it reacting with water vapour in the air = need to dab oil off

Burns with a yellow flame
Produces a white powder (shown as a white mist)
Universal indicator solution goes: Purple
pH: 14

Na2O(s) - ionic

9

Information about magnesium and oxygen?

Magnesium has a reactive oxide layer - scraped off with sandpaper

Burns with a white flame
Produces a white powder (shown as a white mist)
Universal indicator solution goes: Purple
pH: 10

MgO(s) - ionic

10

Information about aluminium and oxygen?

Aluminium is an explosive grey powder

Burns with a white flame and gives orange sparks
Produces a white powder (shown as a white mist)
Universal indicator solution goes: Green
pH: 7

Al2O3(s) - ionic (with a degree of covalency)

11

Information about silicon and oxygen?

You have to heat it very strongly for a reaction

pH: 7

SiO2 - macromolecular

12

Information about phosphorus and oxygen?

Red phosphorus is used (white phosphorus will react in air spontaneously) - allotropes

Burns with a orange flame
Produces a white powder (shown as a white mist)
Universal indicator solution goes: Red
pH: 1

P4O10(s) - covalent
P4O6 - can be formed with a lack of O2

13

Information about sulfur and oxygen?

Burns with a pale blue flame
Produces a colourless gas
Universal indicator solution goes: Red

SO2 - pH 3

SO3 can also form but requires high temperatures and a catalyst
pH 1

14

What are the natural formed of phosphorus and sulfur?

P4
S8

15

What is the bonding of period 3 oxides?

Na2O - ionic
MgO - ionic
Al2O3 - ionic (degree of covalency)
SiO2 - macromolecular covalent
P4O10 - covalent
SO2 - covalent

16

What are the melting point trends of period 3 oxides?

Na2O
Increase to MgO
Slight decrease to Al2O3 (not below Na2O)

SiO2, P4O10 and SO3 all decrease from then

17

Which period 3 oxides react with water?

Na2O -> NaOH
MgO -> Mg(OH)2

P4O10 -> H3PO4 (phosphoric acid)
SO2 -> H2SO3 (sulfurous acid)
SO3 -> H2SO4 (sulfuric acid)

18

Which period 3 oxides don’t react with water? Why?

Al2O3 and SiO2

They are insoluble in water

19

What ions are present in the period 3 oxide + water solutions? pH of the solutions?

NaOH -> Na+ + OH- (pH 14)
MgO -> Mg2+ + OH- (pH 10)

H3PO4 -> H+ + H2PO4- (pH 2)
H2SO3 -> H+ + HSO3- (pH 3)
H2SO4 -> H+ + HSO4- (pH 4)

20

What are some equations for period 3 oxides with an acid?

Na2O + 2HCl -> 2NaCl + H2O
Na2O + H2SO4 -> Na2SO4 + H2O

MgO + 2HCl -> MgCl2 + H2O
MgO + H2SO4 -> MgSO4 + H2O

21

What are some equations for period 3 oxides with alkaline?

SiO2 + 2NaOH -> Na2SiO3 + H2O

P4O10 + 12NaOH -> 4Na3PO4 + 6H2O
H3PO4 + 3NaOH -> Na3PO4 +3H2O

SO2 + NaOH -> NaHSO3
NaHSO3 + NaOH -> Na2SO3 + H2O

SO3 + NaOH -> NaHSO4

22

What are some equations with Al2O3 - acid or base?

Al2O3 will react with an acid and a base - amphoteric

Al2O3 + 6HCl -> 2AlCl3 + 3H2O

Al2O3 + 2NaOH + 3H2O -> 2NaAl(OH)4
(Needs Hot, conc NaOH)

It is insoluble in water