2.4 Period 3 Properties Flashcards
Sodium
In Water
Vigorous reaction pH= 13-14 Fizz Effervescence 2Na + 2H2O → 2NaOH
Sodium
In Oxygen
White Solid
Yellow Flame
4Na + O2 → 2Na2O
Magnesium
In Water
Less Vigorous
Small Fizz
Mg + 2H2O → Mg(OH)2 + H2
Magnesium
In Oxygen
Bright White
2Mg + O2 → 2MgO
Aluminium
In Oxygen
White powder
White Flame
2Al + 3O2 → 2Al2O3
Silicon
In Water
White Powder
White Flame
Si + O2 → SiO2
Phosphorus
In Oxygen
Glowing Bright White
P4 + 5O2 → P4O10
Sulfur
In Oxygen
Choking Gas
S8 + 8O2 → 8SO2
Chlorine
In Water
Dissolves
Pale Green solution
Cl2 + H2O → HClO + HCl
HClO will kill bacteria
Trends in Melting Point of Period 3 Elements
Increases Na→ Al
1) Nuclei of atom is more +ve charged
2) Sea of e- is more -ve
3) Greater amount of attraction
Silicon
1) Giant covalent has many strong bonds to break
P4 → Cl2
1) P4 has weak VanDeWaals
2) S8 is larger than P4 so more VanDeWaals
3) Cl2 is very small so has weakest bonds
Sodium Oxide
In Water
Dissolves
pH= 13-14
Na2O + H2O → 2Na+ + 2OH-
Sodium Oxide
In Acid
Basic Oxide
Na2O + 2HCl → 2NaCl + H2O
Magnesium Oxide
In Water
Not very soluble but dissolves
pH =9
MgO + H2O → Mg(OH)2
Magnesium Oxide
In Acid
Basic Oxide
MgO + H2SO4 → MgSO4 + H2O
Aluminium Oxide
In Acid
Insoluble
Amphoteric
Al2O3 + 6HCl → 2AlCl3 + 3H2O
Aluminium Oxide
In Alkalis
Insoluble
Amphoteric
Al2O3 + NaOH +3H2O → 2NaAl(OH)4
Silicon Dioxide
In Alkalis
Insoluble
pH = 7
Weak Acid
SiO2 + 2NaOH → Na2SiO3 + H2O
Phosphorus Oxide
P4O10
In Water
Violently reacts
P4O10+ 6H2O → 4H3PO4
Phosphorus Oxide
In Alkali
Acidic Oxide
pH= 1-2
P4O10 + 12NaOH → 4Na3PO4 + 6H2O
Sulfur Dioxide
In Water
Not violent
SO3 + H2O → H2SO4
Sulfur Dioxide
In Alkali
SO3 + NaOH → NaHSO4
Strong Acidic Oxide
pH= 0-1
Trends in the melting points of Period 3 OXIDES
Giant Structure
1) Na2O → SiO2
2) High energy to break strong bonds
P4O10, SO2, SO3
1) simple molecular
2) energy to break VanDeWaals
3) varies with size, polarity, shape
