2.4 - Period 3 Flashcards
Period 3 metal oxides are ____ compounds?
Basic
Equation: Reaction of Sulfur & Oxygen?
S₈ + 8O₂ |> 8SO₂
Exceptions of Period 3 elements that react exothermically with oxygen to form oxides?
Argon
Chlorine
Equation: Al₂O₃ & HCl
Al₂O₃ + 6HCl |> 2AlCl₃ + 3H₂O
Equation: Al₂O₃ & HNO₃
Al₂O₃ + 6HNO₃ |> 2Al(NO₃)₃ + 3H₂O
Equation: Al₂O₃ & NaOH
Al₂O₃ + 2NaOH + 3H₂O |> 2NaAl(OH)₄
Why are [Al(H₂O)₆]³⁺ ions Acidic?
charge on Al³⁺ ion causes electron density in water molecule to move closer to the metal ion & polarises the water molecule, breaking one of the bonds & donating a proton
Reaction of [Al(H₂O)₆]³⁺, H₂O & OH⁻
[Al(H₂O)₅OH]²⁺ + H₂O [Al(H₂O)₄(OH)₂]⁺ + H₃O⁺
Observations: Reaction of Sulfur & Oxygen
Blue Flame
Choking Gas
Observations: Reaction of Phosphorus & Oxygen
White Flame
White Fumes
Observations: Reaction of Silicon & Oxygen
v. slow
Observations: Reaction of Aluminium & Oxygen
v. slow
White Solid forms
Observations: Reaction of Silicon & Water
Does not React with Water
Period 3 ____ oxides are Basic
Metal
Why are the Period 3 Metal Oxides Basic?
Contain O²⁻ ions that react with water to form OH⁻
Equation: Reaction of MgO & H₂O?
MgO + H₂O |> Mg(OH)₂
Equation: Reaction of Na₂O & H₂O?
Na₂O + H₂O |> 2NaOH
pH of NaOH?
12-14
NaOH: Strong or weak
Strong Base
pH of Mg(OH)₂?
8-10
Why does Mg(OH)₂ have a lower pH?
less OH⁻ in solution because Mg(OH)₂ is sparingly soluble
H₂SO₃: Strong or weak
Weak Acid - Equilibrium lies to the left
pH of H₂SO₃?
2-3
pH of H₂SO₄?
0-2
pH of H₃PO₄?
0-2
H₃PO₄: Strong or weak
Strong Acid
