UNIT 2 Section 3 - Period 3 Elements

Question 1

What period 3 elements react with water

Answer 1

Sodium
Magnesium
Sulfur dioxide
Sulfur trioxide
Phosphorus

Question 2

How does sodium react with water

Answer 2

Reacts vigouroulst with cold water and forms a molten ball on the surface as H2 gas is formed

Question 3

Write the equation for the reaction between sodium and water

Answer 3

2Na + 2H2O —> 2NaOH + H2

Question 4

How does magnesium react with water and how can you know the reaction has occurred

Answer 4

Magnesium reacts very slowly with water and you can know the reaction has happened as a weak alkaline solution will form

Question 5

Write the equation for magnesium reacting with cold water

Answer 5

Mg + 2H2O —-> Mg(OH)2 + H2

Question 6

What pH solution does magnesium with cold water produce and why

Answer 6

Forms a weakly alkaline solution as magnesium hydroxide is not very soluble so relatively few hydroxide ions are produced

Question 7

What is the reaction between magnesium and steam like

Answer 7

Reacts much faster then with water and forms magnesium oxide

Question 8

Write the equation for the reaction between magnesium and steam

Answer 8

Mg + H2O —-> MgO + H2

Question 9

What is the solution produced when sodium reacts with water adn why

Answer 9

It is alkaline as the sodium hydroxide is soluble in water and forms OH- ions which make is alkaline

Question 10

Is the solution produced by magnesium reacting with water more or less alkaline then when sodium reacts with water and why

Answer 10

The sodium solution is more alkaline as the NaOH is more soluble and therefore more ions will dissociate

Question 11

What simple covalent oxides form acidic solution when they react with water

Answer 11

P4O
SO2
SO3

Question 12

Write an equation for the reaction between phosphorus oxide and water

Answer 12

P4O10 + 6H2O + 4H3PO4

Question 13

Write an equation when sulfur dioxide reacts with water

Answer 13

SO2 + H2O ——> H2SO3

Question 14

Write an equation where sulfur trioxide reacts with water

Answer 14

SO3 + H2O —> H2SO4

Question 15

Does silicon dioxide react with water or not and why

Answer 15

No it doesn’t as it is insoluble in water as it is a giant covalent structure

Question 16

What can silicon dioxide react with

Answer 16

Acids and bases to form salts

Question 17

What does aluminium oxide react with and why

Answer 17

React with acids and bases but it can also act as an acid and a base

Doesn’t react with water as it has partially ionic and partially covalent bonds so it is insoluble in water

Question 18

What do period 3 elements form when they react with oxygen

What is the usual trend and which is the anomaly to this

Answer 18

They form oxides and are usually oxidised to thier highest oxidation state

SO2 is the exception as Sulfur has an oxidation state of 4 when it can have higher

Question 19

What is the overall general equation when a period 3 element reacts with oxygen

Answer 19

Element + oxygen —> oxide

Question 20

Write the equation for the reaction between oxygen and sodium

What is the reaction like

Answer 20

2 Na + 1/2 O2 —> Na2O

Vigourous

Question 21

Write the equation for the reaction between oxygen and magnesium

What is the reaction like

Answer 21

Mg + 1/2 O2 —> MgO

Vigorous

Question 22

Write the equation for the reaction between oxygen and aluminium

What is the reaction like

Answer 22

2Al + 1.5 O2 —-> Al2O3

Slow

Question 23

Write the equation for the reaction between oxygen and silicon

What is the reaction like

Answer 23

Si + O2 —> SiO2

Slow

Question 24

Write the equation for the reaction between oxygen and phosphorus

What is the reaction like

Answer 24

P4 + 5O2 —-> P4O10

Spontaneously combusts

Question 25

Write the equation for the reaction between oxygen and sulfur What is the reaction like

Answer 25

S + O2 —> SO2 Burns steadily

Question 26

What are the flame results for period 3 oxides

Answer 26

Na2O- yellow MgO- brilliant white Al2O3- N/A SiO2- N/A P4O10- brilliant white SO2- blue

Question 27

What is the trend is melting points in period 3 oxides

Answer 27

The ionic substances of Na2O, MgO and Al2O3 all have the highest melting points and they form giant ionic lattices SiO2 has a higher melting point then the simple covalent molecules are it has a giant macromolecular structure and strong covalent bonds P4O10 and SO3 are the lowest melting points as they have simple molecular formula and are attracted with weak intermolecular forces of VDW and therefore have relatively low MP

Question 28

Which period 3 oxides react with bases

Answer 28

SiO2 P4O SO2 SO3

Question 29

Which period 3 elements react with acids

Answer 29

Na2O MgO

Question 30

Which period 3 element reacts with both acids and bases and why can it do that

Answer 30

Aluminium as it is amphoteric and can act as a base or acid due to its properties

Question 31

Write the equation for the reaction between sodium oxide and acid

Answer 31

Na2O + 2HCL —-> 2NaCl + H2O

Question 32

Write the equation between magnesium oxide and acid

Answer 32

MgO + H2SO4 —-> MgSO4 + H2O

Question 33

Write the equation for the reaction between silicon dioxide and alkaline

Answer 33

SiO2 + 2NaOH —-> NaSiO3 + H2O

Question 34

What is the reaction between phosphorus oxide and alkali

Answer 34

P4O10 + 12NaOH —-> 4Na3PO4 + 6H2O

Question 35

Write the equation between the sulfur dioxide and alkali

Answer 35

SO2 + 2NaOH —> Na2SO3 + H2O

Question 36

Write the equation between sulfur trioxide and alkali

Answer 36

SO3 + 2NaOH —> Na2SO4 + H2O

Question 37

Write the equation when aluminium oxide and acid react

Answer 37

Al2O3 + 3H2SO4 —> Al2(SO4)3 + 3H2O

Question 38

What is the equation when aluminium oxide reacts with alkali

Answer 38

Al2O3 + 2NaOH + 3H2O —> 2NaAl(OH)4