Topic 22: Periodicity Y2

Question 1

Type of reaction of p3 elements

Answer 1

Redox

Question 2

Elements that react with cold water

Answer 2

Na, Mg and Cl

Question 3

Sodium and water observation

Answer 3

Vigorous reaction
Floats and fizzes rapidly, melts due to the heat released

Question 4

Sodium and water equation

Answer 4

2Na(s) + 2H2O(l) —> 2NaOH(aq) + H2(g)

Question 5

Magnesium and water observation

Answer 5

Slow at room temp, few bubbles formed after days

Question 6

Which solution is more alkaline, one produced with Mg or Na and water

Answer 6

NaOH is more alkaline than Mg(OH)2 because Mg(OH)2 is only sparingly soluble

Question 7

Mg and water equation

Answer 7

Mg(s) + 2H2O(l) —> Mg(OH)2(aq) + H2(g)

Question 8

Mg and steam reaction

Answer 8

Mg(s) + 2H2O(g) —> MgO(s) + H2(g) (much faster reaction)

Question 9

Sodium and oxygen observation

Answer 9

Yellow flame

Question 10

Sodium and Oxygen equation

Answer 10

2Na(s) + 1/2O2(g) —> Na2O(s)

Question 11

Mg and O observation

Answer 11

Bright white flame (white powder)

Question 12

Mg and O equation

Answer 12

2Mg(s) + O2(g) —> 2MgO(s)

Question 13

Al and O observation

Answer 13

Burns brightly if powdered else wont react as oxide layer is strongly bonded so will prevent reaction (produces white powder)

Question 14

Al and O equation

Answer 14

4Al(s) + 3O2(g) —> 2Al2O3(s)

Question 15

Si and O equation

Answer 15

If heated strongly
Si(s) + O2(g) —> SiO2(s)

Question 16

Red phosphorus and oxygen

Answer 16

Heated before it reacts

Question 17

White phosphorus and oxygen

Answer 17

Spontaneously ignites in air and white smoke is given off

Question 18

Allotropes

Answer 18

Same element with atoms arranged differently like red and white phosphorus

Question 19

Phosphorus and oxygen equation

Answer 19

4P(s) + 5O2(g) —> 2P2O5 (g)

Question 20

Bonding in Al2O3

Answer 20

Ionic with covalent character as Al is a small high positive charge ion which distorts the electron cloud of O2-

Question 21

Electronegativity and covalent character trend

Answer 21

The bigger the difference in electronegativity, the less covalent character. Think about an element bonding with itself, no difference in electronegativity, completely covalent.

Question 22

Metal Oxides bonding

Answer 22

Giant ionic lattice

Question 23

Silicon oxide structure

Answer 23

Giant covalent (macromolecular)

Question 24

Phosphorous and sillicon structures

Answer 24

Covalent, molecular

Question 25

Phosphorous and Silicon oxides melting point order

Answer 25

P4O10 > SO3 > SO2 Increase in IMFs

Question 26

Basic oxides

Answer 26

Na and Mg

Question 27

Sodium oxide and water equation

Answer 27

Na2O(s) + H2O(l) ---> 2Na+(aq) + 2OH-

Question 28

Mg oxide and water equation

Answer 28

MgO(s) + H2O(l) ---> Mg(OH)2(s) <===> Mg^2+ (aq) + 2OH-(aq)

Question 29

Insoluble oxides

Answer 29

Al and Si

Question 30

Acidic Oxides

Answer 30

P and S

Question 31

Phosphorous pentoxide and water equation

Answer 31

P4010(s) + 6H2O(l) ---> 4H3P04(aq) violent reaction then ionises H3PO4(aq) <===> H+(aq) + H2PO4-(aq)

Question 32

Sulfur dioxide and water

Answer 32

Fairly soluble in water making sulfurous acid which partially dissociates

Question 33

Sulfur dioxide and water equations

Answer 33

SO2(g) + H2O(l) ---> H2SO3(aq) H2SO3(aq) <===> H+(aq) +HSO3-(aq)

Question 34

Sulfur trioxide and water equation

Answer 34

Violent SO3(g) + H2O(l) ---> H2SO4(aq) ---> H+(aq) + HSO4-(aq)

Question 35

Why sodium oxide reacts with water

Answer 35

Oxide ion (very strong base) readily reacts with water to produce hydroxide ions forming a strongly alkaline solution

Question 36

Why aluminium oxide doesnt react with water

Answer 36

Ionic but the bonding is too strong for the ions to be separated, partly because of the additional covalent bonding it has.

Question 37

Sodium oxide and sulfuric acid

Answer 37

Na2O(s) + H2SO4(aq) ---> Na2SO4(aq) + H2O(l)

Question 38

Magnesium oxide and hydrochloric acid

Answer 38

MgO(s) + 2HCl(aq) ---> MgCl2(aq) + H2O(l)

Question 39

Amphoteric

Answer 39

Able to react as a base and as an acid like aluminium oxide

Question 40

Aluminium oxide and HCl

Answer 40

Al2O3(s) + 6HCl(aq) ---> 2AlCl3(aq) + 3H2O(l)

Question 41

Aluminium oxide and NaOH

Answer 41

NaOH has to be hot and conc. Al2O3(s) + 2NaOH(aq) + 3H2O(l) ---> 2NaAl(OH)4(aq)

Question 42

Silicon dioxide and NaOH

Answer 42

NaOH has to be hot and conc. SiO2(s) + 2NaOH(aq) ---> Na2SiO3(aq) + H2O(l) Colourless solution

Question 43

Phosphorous Pentoxide and NaOH

Answer 43

Actually H3PO4 and NaOH as it forms that when in water. Happens in 3 stages as phosphoric acid has 3 OH groups with an acidic H+ so reacts in 3 stages.

Question 44

Phosphorous Pentoxide and NaOH equations

Answer 44

H2PO4(aq) + NaOH(aq) ---> NaH2PO4(aq) + H2O(l) NaH2PO4(aq) + NaOH(aq) ---> Na2HPO4(aq) + H2O(l) Na2HPO4(aq) + NaOH(aq) ---> Na3PO4(aq) + H2O(l) Overall: 3NaOH(aq) + H3PO4(aq) ---> Na3PO4(aq) + 3H2O(l)

Question 45

Sulfur dioxide and NaOH

Answer 45

SO2(aq) + NaOH(aq) ---> NaHSO3(aq) NaHSO3(aq) + NaOH(aq) ---> Na2SO3(aq) + H2O(l)