Unit 2: Section 3- Period 3 Elements (2.4)

Question 1

What subshell is the outer electron in in Mg and Na?

Answer 1

s subshell

Question 2

What are the different reactions between magnesium and sodium with water?

Answer 2

sodium more reactive, more readily ionises
magnesium reacts slowly with cold water

Question 3

State the reaction between sodium and cold water

Answer 3

2Na + 2H2O → 2NaOH + H2

Question 4

State the reaction between magnesium and cold water

Answer 4

Mg + 2H2O → Mg(OH)2 + H2

Question 5

State the reaction between magnesium and steam

Answer 5

Mg (s) + H2O (g) → MgO (s) + H2 (g)

Question 6

How do the period 3 elements react with oxygen?

Answer 6

they all form oxides (except argon) that take up their highest oxidation state

Question 7

What is the exception for sulphur in oxidation states when reacting with oxygen?

Answer 7

sulphur forms an oxide where the oxidation state of sulphur is +4

Question 8

What is the oxidation state of the period 3 element in an oxide?

Answer 8

+3 (except sulphur)

Question 9

What visible changes can you see when sodium reacts with oxygen?

Answer 9

• white solid formed
• yellow flame

Question 10

State the equation of sodium reacting with oxygen

Answer 10

4Na (s) + O2 (g) → 2Na2O (s)

Question 11

What colour flame do magnesium, aluminium, silicon and phosphorous burn with?

Answer 11

white flame

Question 12

What colour flame does sulphur burn with?

Answer 12

blue flame

Question 13

State the equation between sulphur and oxygen

Answer 13

S (s) + O2 (g) → SO2 (g)

Question 14

State the equation for magnesium reacting with oxygen

Answer 14

2Mg (s) + O2 (g) → 2MgO (s)

Question 15

State the equation for aluminium reacting with oxygen

Answer 15

4Al (s) + 3O2 (g) → 2Al2O3 (s)

Question 16

State the equation for silicon reacting with oxygen

Answer 16

Si (s) + O2 (g) → SiO2 (s)

Question 17

State the equation for phosphorous reacting with oxygen

Answer 17

4P (s) + 5O2 (g) → P4O10 (s)

Question 18

What are properties of sulphur dioxide (SO2)

Answer 18

acidic, choking gas

Question 19

What are the three giant ionic lattice structures of period 3 oxides?

Answer 19

Na2O, MgO, Al2O3

Question 20

Describe the structure of SiO2

Answer 20

macromolecular, giant covalent oxide

Question 21

Name the structure of P4O10 and SO2

Answer 21

simple molecular structures

Question 22

How do the structures of period 3 metal oxides effect the melting points?

Answer 22

these different structures lead to period 3 metal oxides having different melting points

Question 23

What type of melting point do ionic metal oxides have?

Answer 23

high

Question 24

Explain the trend in melting point from Na2O to Al2O3

Answer 24

melting point increases due to the increased charge of the cation, which makes the electrostatic forces even stronger

Question 25

What happens to the trend in melting point after Al2O3?

Answer 25

there is an increase, as SiO2 is macromolecular, with very strong covalent bonds, and a very high MP

Question 26

What type of melting point does SiO2 have?

Answer 26

very high, strong covalent bonds, high energy needed to break

Question 27

What happens to the trend in melting point after SiO2?

Answer 27

it drops

Question 28

What type of melting point does P4010 and SO2 have?

Answer 28

lower melting point because they are simple molecular oxides P4O10 has higher than SO2 because of more electrons, so larger van der waals.

Question 29

What do metal ionic oxides form when they react with water?

Answer 29

hydroxides which are alkaline

Question 30

State the reaction between Na2O and water, and the pH of the product

Answer 30

Na2O + H2O → 2NaOH pH of 13

Question 31

State the reaction between MgO and water, and the pH of the product

Answer 31

MgO (s) + H2O (l) → Mg(OH)2 (s) pH of 9

Question 32

Explain why the pH of Mg(OH)2 is lower than 2NaOH

Answer 32

because Mg(OH)2 is only slightly soluble, so it only slightly dissociates difference in solubility due to Mg ion being smaller, so it has a stronger lattice, so fewer OH- ions produced

Question 33

State the reaction between phosphorous oxide and water, and give the pH of the product

Answer 33

P4O10 (s) + 6 H2O (l) → 4H3PO4 (aq) pH of 0

Question 34

State the reaction between SO2 and water, and give the pH of the product

Answer 34

SO2(g) + H2O (l) → H2SO3 (aq) pH of 3

Question 35

State the reaction between SO3 and water, and give the pH of the product

Answer 35

SO3 (g) + H2O (l) → H2SO4 (aq) pH of 0

Question 36

What are the three types of oxides?

Answer 36

acidic basic amphoteric

Question 37

What period 3 oxides are examples of basic oxides?

Answer 37

Na2O MgO

Question 38

What period 3 oxides are examples of acidic oxides?

Answer 38

P4O10 SO2 SO3

Question 39

What period 3 oxides are examples of amphoteric oxides?

Answer 39

Al2O3

Question 40

What happens to period 3 basic oxides in reactions?

Answer 40

react with acids to form a salt and water

Question 41

What happens to period 3 acidic oxides in reactions?

Answer 41

react with bases to form salts

Question 42

What happens to period 3 amphoteric oxides in reactions?

Answer 42

react with acids or bases they can act as both an acid an an alkali