properties of period 3 elements and their oxides

Question 1

what is more reactive, Na or Mg?

Answer 1

Sodium is ​more reactive​ than magnesium as it only has to lose one electron to form an ion, whereas magnesium has to lose two electrons. Therefore​ less energy is required ​to ionise sodium making it more reactive.

Question 2

Na reaction with water.
Equation and observations

Answer 2

2Na(s)+ 2H2O(l) → 2NaOH(aq) + H2(g)
Reacts vigorously
forms a ball
fizzing

Question 3

Mg reaction with water and steam
Equation and observations

Answer 3

Mg(s) + 2H2O(l) → Mg(OH)2(aq) + H2(g)
Bright white light
White solid
reacts faster with steam: Mg(s) + H2O(l) → MgO(s) + H2(g)

Question 4

Na reaction with oxygen
Equations and observations

Answer 4

4Na (s) + O2 (g) → 2Na2O (s)
vigorous reaction
bright yellow flame
white solid

Question 5

Mg reaction with oxygen
Equations and observations

Answer 5

2Mg (s) + O2 (g) → 2MgO (s)
vigorous reaction
bright white flame
white solid
more intense if lowered into jar of oxygen

Question 6

Al reaction with oxygen
Equations and observations
Why does it seem to be unreactive?

Answer 6

4Al (s) + 3O2 (g) → 2Al2O3 (s)
fast reaction
powdered Al
bright white flame
white powder
always coated in a strongly bonded layer of oxide to prevent further reaction so seems unreactive

Question 7

Si reaction with oxygen
Equations and observations

Answer 7

Si (s) + O2 (g)→ SiO2 (s)
slow reaction
powdered Si burns if strongly heated in oxygen
bright white sparkles
white powder

Question 8

P reaction with oxygen
Equations and observations

Answer 8

4P (s) + 5O2 (g) → P4O10 (s)
White P is spontaneous combustion
white flame
white smoke
white solid
Red P must be heated before reaction

Question 9

S reaction with oxygen
Equations and observations

Answer 9

S (s) + O2 (g) → SO2 (g)
gentle reaction
blue flame
For SO3 to form, a catalyst must be used and the reaction must take place at a very high temperature
The equation for this reaction is:
2S (s) + 3O2 (g) → 2SO3 (g)

Question 10

Oxides of Na, Mg, Al
structure and bonding

Answer 10

giant ionic lattice
strong electrostatic forces of attraction between oppositely charged ions
spreads throughout compound
gives it a high melting point
lots of energy required to overcome

Question 11

Bonding in Al2O3

Answer 11

ionic/covalent
metal + non-metal
due to it being a small ion with a large positive charge
the Al+3 ion can polarize electron charge from O-2 ion. That can give the bond some covalent character.

Question 12

SiO2
structure and bonding

Answer 12

macromolecular
many strong covalent bonds spread throughout structure
a lot of energy required to break covalent bonds

Question 13

oxides of P,S
structure and bonding

Answer 13

simple molecular
weak wan der waals

Question 14

trends in melting points for oxides

Answer 14

Na2O < MgO > Al2O3 >
SiO2 > P4O10 > SO3 > SO2

Question 15

Na2O reaction with water
equations, ionic , PH

Answer 15

Na2O + H2O → 2NaOH
Na2O + H2O → 2Na+ + 2OH-
PH 13-14
strongly alkaline

Question 16

MgO reaction with water
equations, ionic , PH

Answer 16

MgO + H2O → Mg(OH)2
MgO + H2O → Mg(2+) + 2OH-
PH 9
weakly alkaline

Question 17

Al2O3, SiO2 reaction with water

Answer 17

insoluble
al— amphoteric
Si— acidic

Question 18

P4O10 reaction with water
equations, ionic , PH

Answer 18

P4O10 + 6H2O → 4H3PO4
P4O10 + 6H2O → 12H+ + 4PO3