period 3 elements + oxides

what is observed when sodium reacts with oxygen (2)

burns with a yellow flame

produces a white solid

what is observed when magnesium/aluminium/silicon/phosphorous react with oxygen

burns with a white flame

produces a white solid smoke

what is observed when sulfur reacts with oxygen

burns with a blue flame

produces an acidic choking gas

equation for the reaction of sodium and water

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

what is observed when sodium reacts with water and why

effervescence caused by the production of hydrogen gas

equation for the reaction of magnesium and cold water

Mg(s) + 2H₂O → Mg(OH)₂(aq) + H₂

what is the rate of reaction like between magnesium and cold water

very slow

equation for the reaction of magnesium with steam

Mg(s) + H₂O(g) → MgO(s) + H₂(g)

what is the appearance of MgO

white solid

what is the trend in solubility of the hydroxides across the period

increases

equation for the reaction of sodium with oxygen

4Na(s) + O₂(g) → 2Na₂O(s)

equation for the reaction of magnesium with oxygen

2Mg(s) + O₂(g) → 2MgO(s)

equation for the reaction of aluminium with oxygen

4Al(s) + 3O₂(g) → 2Al₂O₃(s)

equation for the reaction of silicon with oxygen

Si(s) + O₂(g) → SiO₂(s)

equation for the reaction of phosphorous with oxygen

4P(s) + 5O₂(g) → P₄O₁₀(s)

equation for the reaction of sulfur with oxygen

S(s) + O₂(g) → SO₂(g)

what is slightly unusual about the structure and bonding of Al₂O₃

it’s a giant ionic lattice but has significant covalent character

the Al3+ ion has a high charge density so can approach and distort the electron cloud of the oxide ions

which period three oxides are ionic

Na₂O

MgO

Al₂O₃

what is the order of melting points of the ionic oxides (smallest to biggest)

Na₂O

Al₂O₃

MgO

how can you experimentally prove that the ionic oxides contain ions

melt the solids and show that they conduct electricity

which period three oxides have simple molecular structure

P₄O₁₀

SO₂

which intermolecular forces are present in the simple molecular oxides

VDWF’s

permanent dipoles

which simple molecular oxide has the highest melting point and why

P₄O₁₀

it is a larger molecule so has more electrons

therefore the VDWF’s between it’s molecules are stronger

which period three oxide is a giant covalent molecule

SiO₂

how is aluminium metal protected from corrosion

insoluble layer of aluminium oxide

what type of solutions do metal ionic oxides dissolve in water to form

alkaline

equation for the reaction of sodium oxide with water

Na₂O(s) + H₂O (l) → 2NaOH(aq)

what is the pH of NaOH

14

describe the solubility of Mg(OH)₂

sparingly soluble

what is the pH of Mg(OH)₂

9

state a use of Mg(OH)₂

antacid

what is the pH of the solution formed when aluminium oxide or silicon dioxide react with water

7

what is the acid-base character of aluminium oxide

amphoteric

why are the ionic oxides basic

the oxide ions accept protons to become hydroxide ions

ionic equation for oxide ions to hydroxide ions

O^2-(aq) + H₂O(l) → 2OH^-(aq)

why doesn’t aluminium oxide dissolve in water

its ionic lattice is very strong

why doesn’t silicon dioxide dissolve in water

its macromolecular structure is very strong

what type of solutions do the simple molecular covalent oxides dissolve in water to form

acidic

equation for the reaction of phosphorous (v) oxide with water

P₄O₁₀(s) + 6 H₂O (l) → 4H₃PO₄(aq)

what is the pH range of H₃PO₄

0-2

equation for the reaction of sulfur dioxide with water

SO₂ (g) + H₂O (l) → H₂SO₃ (aq)

what is the pH of H₂SO₃

3

equation for the reaction of sulfur trioxide with water

SO₃ (g) + H₂O (l) → H₂SO₄ (aq)

what is the pH of H₂SO₄

0

why do the covalent oxides form acidic solutions

they have a strongly positive dipole on the atom that is not oxygen which attracts the lone pair on water molecules, releasing H+ ions

ionic equation of covalent oxides to hydrogen ions

MO(s) + H₂O(l) → MO(OH)^-(aq) + H⁺(aq)

pattern of acid + base reactions

acid + base → salt + water

full equation for the reaction of sodium oxide with hydrochloric acid

Na₂O(s) + 2HCl(aq) → 2NaCl(aq) + H₂O(l)

ionic equation for the reaction of sodium oxide with an acid

Na₂O (s) + 2H+ (aq) → 2Na+ (aq) + H2O (l)

full equation for the reaction of magnesium oxide with hydrochloric acid

MgO(s) + 2HCl(aq) → MgCl₂(aq) + H₂O(l)

ionic equation for the reaction of magnesium oxide with an acid

MgO(s) + 2H⁺(aq) → Mg²⁺(aq) + H₂O(l)

formula of a phosphate ion

PO₄^3-

formula of a sulfate ion

SO₄^2-

full equation for the reaction of aluminium oxide with hydrochloric acid

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

ionic equation for the reaction of aluminium oxide with an acid

Al₂O₃(s) + 6H⁺(aq) → 2Al³⁺(aq) + 3H₂O(l)

full equation for the reaction of aluminium oxide with hot concentrated sodium hydroxide

Al₂O₃(s)+ 2NaOH(aq) + 3H₂O(l) → 2NaAl(OH)₄(aq)

ionic equation for the reaction of aluminium oxide with a hydroxide

Al₂O₃(s)+ 2OH^-(aq) + 3H₂O(l) → 2Al(OH)₄^- (aq)

full equation for the reaction of silicon dioxide with hot concentrated sodium hydroxide

SiO₂(s) + 2NaOH(l) → Na₂SiO₃(aq) + H₂O(l)

full equation for the reaction of silicon dioxide with calcium oxide

SiO₂(s) + CaO(s) → CaSiO₃(l)

what 2 things occur in the blast furnace

production of iron

removal of SiO₂

why is SiO₂ removed in the blast furnace

it is an impurity

what is the colloquial name for calcium silicate (CaSiO₃)

slag

full equation for the reaction of phosphorous (v) oxide with sodium hydroxide

P₄O₁₀(s) + 12NaOH(aq) → 4Na₃PO₄ (aq) + 6H₂O(l)

full equation for the reaction of sulfur dioxide with sodium hydroxide

SO₂(g) + 2NaOH(aq) → Na₂SO₃(aq) + H₂O(l)

full equation for the reaction of sulfur trioxide with sodium hydroxide

SO₃(g) + 2NaOH(aq) → Na₂SO₄(aq) + H₂O(l)

what is the product if you add a basic oxide to phosphorous (v) oxide

phosphate salt formed (PO₄)

trend in acidity across the period from left to right

increases