Properties Of Period 3 Elements

Question 1

Sodium reaction w water

Answer 1

2Na(s) + 2H2O —-> 2NaOH + H2

Question 2

Magnesium reaction w water

Answer 2

Mg(s) + 2H2O —-> Mg(OH)2 + H2

Question 3

Sodium reaction w oxygen

Answer 3

2Na(s) + 1/2 O2 —-> Na2O

Question 4

Magnesium reaction w oxygen

Answer 4

2Mg(s) + O2 (g) —-> 2MgO

Question 5

Aluminium reaction w oxygen

Answer 5

4Al (s) + 3O2 (g) —-> 2Al2O3

Question 6

Sodium oxide reaction w water at high high ph

Answer 6

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

Question 7

Magnesium oxide reaction with water (ph 9-10)

Answer 7

MgO(s) + H2O(l) ——> Mg(OH)2 (aq)

Question 8

Sodium oxide + sulfuric acid

Answer 8

Na2O (s) + H2SO4 (aq) —> Na2SO4(aq) + H2O

Question 9

phosphorus reaction with oxygen

Answer 9

P4(s) + 5O2(g) —-> P4O10

Question 10

why does Al2O3 have more covalent character than MgO

Answer 10

Al3+ ion smaller than Mg2+ ion
means Al3+ more polarising than Mg2+
this distorts elctron cloud around O2- ion more so that there is more elctron density shared between two ions

Question 11

what does amphoteric mean

Answer 11

act as acid or base

Question 12

does the size of the metal ion increase or decrease as you go across period 3

Answer 12

decrease
-inc strentgh of ions

Question 13

phosphorus oxide reaction w water

Answer 13

P4O10 + 6H2O —-> 4H3PO4

Question 14

what flame forms when you burn sodium in air and what else is produced

Answer 14

orange flame to produce white solid mixture of sodium iodide and sodium peroxide

Question 15

colour flame when magnesium burns in oxygen

Answer 15

bright white flame