Period 3 elements and oxides

Question 1

What are the physical trends across period 3?

Answer 1

Na,Mg and Al- metallic
Si- metalloid
P, S & Cl- non-metal
Ar- noble gas

Question 2

What type of reaction happens to period 3 elements?

Answer 2

Redox reactions

Question 3

Which period 3 elements react with cold water?

Answer 3

Na, Mg and Cl

Question 4

How does Na react with cold water?

Answer 4

Na reacts vigorously, fizzing rapidly producing a strongly alkaline solution(13-14)

Question 5

How does Mg react with cold water?

Answer 5

Mg reacts very slowly producing a weakly alkaline solution(~10)

Question 6

Why is Na more reactive than Mg?

Answer 6

It takes less energy to lose one electron than to lose two.

Question 7

How does Mg react with steam?

Answer 7

Faster reaction

Question 8

What happens when period 3 elements react with oxygen?

Answer 8

They are oxidised to their highest oxidation states (same as their group numbers) except sulfur.

Question 9

Why is sulfur an exception when it reacts with oxygen?

Answer 9

SO2 is produced which has a +4 oxidation state

High temperature and a catalyst are needed to make SO3 where sulfur has an oxidation state of +6

Question 10

How does Na react with oxygen?

Answer 10

It burns with a yellow flame
Vigorous
White Na2O is produced

Question 11

How does Mg react with oxygen?

Answer 11

It burns with a bright white flame
Vigorous
MgO is produced

Question 12

How does Al react with oxygen?

Answer 12

Slowly (faster if powdered)

Question 13

How does Si react with oxygen?

Answer 13

Slowly

Question 14

How does P react with oxygen?

Answer 14

Red phosphorus must be heated before it reacts with oxygen
White phosphorus spontaneously ignites in air. White smoke is given off
(Red and White P are allotropes)

Question 15

How does S react with oxygen?

Answer 15

Burns steadily with a blue flame

Question 16

What are allotropes?

Answer 16

Atoms of the same element arranged differently

Question 17

What is the bonding and structure in Na2O, MgO and Al2O3?

Answer 17

They have giant ionic lattices and therefore high melting points
It is ionic bonding

Question 18

Why does MgO have a higher melting point than Na2O?

Answer 18

Mg forms 2+ ions, so the bonds are stronger than 1+ Na ions

Question 19

Why does that Al2O3 have a lower melting point than expected?

Answer 19

Highly charged Al3+ ions distort the oxygen electron cloud making the bonds partially covalent

Question 20

What is the bonding and structure in SiO2?

Answer 20

It is covalent bonding

It is a macromolecular structure and therefore a high melting point(strong covalent bonds)

Question 21

What is the bonding and structure in P4O10 and SO2?

Answer 21

It is covalent bonding
They have simple molecular structures and therefore low melting points(weak intermolecular-van der Waals and dipole-dipole)

Question 22

Which oxides of period 3 elements are acidic or alkaline?

Answer 22

Ionic oxides are alkaline

Covalent oxides are acidic

Question 23

What happens when MgO and Na2O react with water?

Answer 23

Hydroxide ions are formed

Both solutions are alkaline

Question 24

Why does NaOH make a stronger alkaline solution than Mg(OH)2?

Answer 24

NaOH is more soluble in water

Question 25

What happens when simple covalent oxides- phosphorus and sulfur- react with water?

Answer 25

They form acidic solutions with a pH 0-2 | They will dissociate in solution forming hydrogen ions and a conjugate base

Question 26

Which oxides are insoluble?

Answer 26

Al2O3 | SiO2

Question 27

Why is SiO2 classed as acidic?

Answer 27

It reacts with bases to form salts

Question 28

Why is Al2O3 amphoteric?

Answer 28

It can act as an acid or a base | Therefore it can react with acids and bases to form salts

Question 29

Write the equation for the reaction that occurs between amphoteric oxides and sulfuric acid

Answer 29

Al2O3(s) + 3H2SO4(aq) → Al2(SO4)3(aq) + 3H2O(l)

Question 30

Write the equation for the reaction that occurs between amphoteric oxides,water and sodium hydroxide

Answer 30

Al2O3(s) + 2NaOH(aq) + 3H2O(l) → 2NaAl(OH)4(aq)

Question 31

What is the equation for the reaction between Mg and water?

Answer 31

Mg(s) + 2H2O(l) → Mg(OH)2(aq) + H2(g)

Question 32

What is the equation for the reaction between Mg and steam?

Answer 32

Mg(s) + H2O(g) → MgO(s) + H2(g)

Question 33

What is the equation for the reaction between Na and oxygen?

Answer 33

2Na(s) + 0.5O2(g) → Na2O(s)

Question 34

What is the equation for the reaction between Mg and oxygen?

Answer 34

Mg(s) + 0.5O2(g) → MgO(s)

Question 35

What is the equation for the reaction between Al and oxygen?

Answer 35

2Al(s) + 1.5O2 → Al2O3(s)

Question 36

What is the equation for the reaction between SI and oxygen?

Answer 36

Si(s) + O2(g) → SiO2(s)

Question 37

What is the equation for the reaction between P and oxygen?

Answer 37

P4(s) + 5O2 → P4O10(s)

Question 38

What is the equation for the reaction between S and oxygen?

Answer 38

S(s) + O2(g) → SO2(g)

Question 39

What is the equation for the reaction between Magnesium oxide and water and the pH?

Answer 39

MgO + H2O → Mg(OH)2 | pH 9-10

Question 40

What is the equation for the reaction between Sodium oxide and water and the pH?

Answer 40

Na2O + H2O → 2NaOH | pH 12-14

Question 41

What is the equation for the reaction between Phosphorus pentoxide and water?

Answer 41

P4O10(s) + 6H2O(l) → 4H3PO4(aq)

Question 42

What is the equation for the reaction between sulfur dioxide and water?

Answer 42

SO2(g) + H2O(l) → H2SO3(aq)

Question 43

What is the equation for the reaction between sulfur trioxide and water?

Answer 43

SO3(l) + H2O(l) → H2SO4(aq)

Question 44

What are the equations for the dissociation of sulfuric acid?

Answer 44

H2SO3(aq) → 2H+(aq) + (SO3)2-(aq) | H2SO4(aq) → 2H+(aq) + (SO4)2-(aq)

Question 45

What are the equations for the dissociation of phosphoric acid?

Answer 45

H3PO4(aq) → 3H+(aq) + (PO4)3-(aq)

Question 46

What is the equation for the reaction between magnesium oxide and sulfuric acid?

Answer 46

MgO(s) + H2SO4(aq) → MgSO4(aq) + H2O(l)

Question 47

What is the equation for the reaction between sodium oxide and hydrochloric acid?

Answer 47

NaO(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l)

Question 48

What is the equation for the reaction between silicon dioxide and sodium hydroxide?

Answer 48

SiO2(s) + 2NaOH(aq) → Na2SiO3(aq) + H2O(l)

Question 49

What is the equation for the reaction between phosphorus pentoxide and sodium hydroxide?

Answer 49

P4O10(s) + 12NaOH(aq) → 4Na3PO4(aq) + 6H2O(l)

Question 50

What is the equation for the reaction between sulfur dioxide and sodium hydroxide?

Answer 50

SO2(g) + 2NaOH(aq) → Na2SO3(aq) + H2O(l)

Question 51

What is the equation for the reaction between sulfur trioxide and sodium hydroxide?

Answer 51

SO3(g) + 2NaOH(aq) → Na2SO4(aq) + H2O(l)