3.2.4 - Period 3 and their oxides Flashcards
Give the equation for the reaction between Al2O3 and NaOH.
Al2O3 (s) + 2NaOH (aq) + 3H2O (l) -> 2NaAl(OH)4
How do you prove experimentally that a compound contains ions?
Melt the solids and show they conduct electricity.
What are the observations for when Mg reacts with steam?
Bright white flame and white solid/powder.
How does Aluminum oxide react with water?
AlO2 is amphoteric, acting as both an acid and a base. Aluminum oxide has both ionic and covalent nature, resulting in it being insoluble in water.
Does electronegativity increase across period 3?
Yes, electronegativity increases across a period because the number of charges on the nucleus increases, attracting the bonding pair of electrons more strongly.
Type of bonding between Phosphorus?
Covalent.
Bonding between sodium?
Ionic.
What are the 2 basic metal oxides?
Sodium and Magnesium.
How do you test for H2 gas?
Test with a lighted splint; a squeaky pop proves the presence of H2 gas.
Why does MgO have a higher boiling point than Al2O3 and Na2O?
MgO has a 2+ charge, while Na has only a +1 charge, leading to greater charge density and stronger attraction to oxygen. Al2O3 has 3+ ions that distort the electron cloud of oxygen, containing some covalent character, requiring less energy to break bonds.
What do Ionic oxides (Na and Mg) form when they are added to water?
They form hydroxides.
Explain how Sodium burns with oxygen and what it forms.
Sodium burns with a yellow flame to produce a white solid.
State how Mg, Al, Si, and P burn with oxygen.
They burn with a white flame to give white solid smoke.
How does S react with oxygen?
S burns with a blue flame to form an acidic choking gas.
Explain how period 3 elements react with a Bunsen burner.
Sodium burns with a yellow flame to produce a white solid. Mg, Al, Si, and P burn with a white flame to produce white solid smoke. S burns with a blue flame to produce an acidic choking gas.
Write an equation for the reaction of excess magnesium oxide with phosphoric acid.
MgO + H3PO4 -> Mg3(PO4)2 + H2O
Reactions of non-metal oxides.
Non-metal oxides react with water to form acids.
Bonding of simple molecular oxides.
Simple molecular oxides have covalent bonds.
Bonding of SiO2.
SiO2 has a giant covalent structure.
How is the aluminum metal ion protected from corrosion?
Aluminum forms a protective oxide layer.
Explain how metal ionic oxide (Na2O) reacts with water to form hydroxides which are alkaline.
Na2O + H2O -> 2NaOH
Why is MgO better than NaOH for treating acidity?
MgO is sparingly soluble and weakly alkaline, preventing excessive alkalinity in water.
How do simple molecular covalent oxides (P4O10) react with water?
P4O10 + 6H2O -> 4H3PO4
How do simple molecular covalent oxides (SO2) react with water?
SO2 + H2O -> H2SO3
Draw the displayed formula for the acids: H2SO4, H2SO3, H3PO4.
H2SO4, H2SO3, H3PO4
Explain how the basic oxides react with acids.
Basic oxides react with acids to form salts and water.
Aluminum acting as an amphoteric oxide ionically.
Al2O3 + 6HCl -> 2AlCl3 + 3H2O
Ionic equations of Period 3 elements reacting to form a salt.
Na2O + 2HCl -> 2NaCl + H2O
Explain the bonding of Al2O3.
Al2O3 is ionic but shows some covalent character.
Describe the reaction of sodium with water, including the chemical equation.
Sodium reacts vigorously with cold water, forming sodium hydroxide and hydrogen gas. The equation is 2Na(s) + 2H2O(l) -> 2NaOH(aq) + H2(g).
Compare magnesium’s reaction with cold water and with steam.
Magnesium reacts slowly with cold water to form magnesium hydroxide, while it reacts readily with steam to produce magnesium oxide and hydrogen gas. The equation for steam is Mg(s) + H2O(g) -> MgO(s) + H2(g).
How do Period 3 elements react with oxygen?
Period 3 elements react with oxygen to form oxides, characterized by bright flames and the production of white solids or gases.
How do the basic oxides of Period 3 react with acids?
Basic oxides like Na2O and MgO react with acids to form salts and water.
Explain the amphoteric behavior of aluminum oxide.
Al2O3 can act as both a base and an acid, reacting with acids and bases.
What happens when silicon dioxide reacts with sodium hydroxide?
SiO2 + 2NaOH -> Na2SiO3 + H2O
Differentiate between the properties of metal and non-metal oxides in Period 3.
Metal oxides are ionic, basic, and have high melting points. Non-metal oxides are covalent, acidic, and have lower melting points.
Describe the structures of ionic and macromolecular oxides in Period 3.
Ionic oxides have giant ionic lattice structures, while macromolecular oxides have giant covalent structures.
How can you experimentally demonstrate that certain Period 3 oxides contain ions?
By melting the solids and demonstrating that they conduct electricity in the molten state.
How does magnesium oxide react with hydrochloric acid?
MgO + 2HCl -> MgCl2 + H2O
Provide the equations for aluminum oxide acting as both a base and an acid.
As a base: Al2O3 + 6HCl -> 2AlCl3 + 3H2O. As an acid: Al2O3 + 2NaOH + 3H2O -> 2NaAl(OH)4.
Describe the trend in oxide acidity and basicity across Period 3.
Oxides transition from basic to acidic across Period 3. Sodium and magnesium oxides are basic, while phosphorus pentoxide and sulfur trioxide are acidic.
Why is magnesium oxide preferred over sodium hydroxide for treating acidification in environments?
Magnesium oxide is sparingly soluble and weakly alkaline, preventing excessive alkalinity in water.
What are the reactions of non-metal oxides like SO2 and P4O10 with water?
SO2 + H2O -> H2SO3 and P4O10 + 6H2O -> 4H3PO4.
What is the reaction for sulfur dioxide?
l) → H2S + O3 (aq)
This illustrates the behavior of sulfur dioxide as an acidic oxide.
What is the reaction for phosphorus pentoxide?
P4O10 (s) + 6 H2O (l) → 4 H3PO4 (aq)
This illustrates the behavior of phosphorus pentoxide as an acidic oxide.
