G.C.E. A-Level Chemistry Grade 12 Unit 6

The thermal stability of Group 2 carbonates increases with the size of the cation.

MgCO3 decomposes at a lower temperature due to the highly polarized carbonate anion attached to the smaller Mg2+ cation.

The solubility of Group 2 hydroxides increases down the group, with Ba(OH)2 being soluble and Mg(OH)2 being sparingly soluble.

<p>Group 2 hydrogen carbonates are not stable at room temperature and only exist in aqueous solutions.</p> Signup and view all the answers

<p>The exception is BeCO3, which is soluble.</p> Signup and view all the answers

<p>The products are lithium oxide, nitrogen dioxide, and oxygen.</p> Signup and view all the answers

<p>Group 1 hydroxides react with carbon dioxide to produce metal carbonates, specifically Na2CO3 from NaOH.</p> Signup and view all the answers

<p>Sodium hydrogen carbonate decomposes to form sodium carbonate, water, and carbon dioxide.</p> Signup and view all the answers

<p>They react vigorously to produce hydrogen gas and relevant metal salts.</p> Signup and view all the answers

<p>Lithium carbonate (Li2CO3) is less stable and decomposes readily.</p> Signup and view all the answers

<p>Thermal stability of group 1 nitrates increases as you move down the group.</p> Signup and view all the answers

<p>The solubility of group 1 halides increases down the group.</p> Signup and view all the answers

<p>They produce metal hydroxides and hydrogen gas.</p> Signup and view all the answers

<p>Carbon monoxide acts as a reducing agent in the production of iron.</p> Signup and view all the answers

<p>Solid carbon dioxide sublimates due to low temperatures and/or high pressures, transitioning directly to gaseous carbon dioxide.</p> Signup and view all the answers

<p>Carbonic acid is formed by dissolving carbon dioxide in water under pressure.</p> Signup and view all the answers

<p>Carbonic acid can dissociate to produce bicarbonate (HCO3-) and hydronium ions (H3O+).</p> Signup and view all the answers

<p>Dinitrogen (N2) is highly stable and inert under normal conditions due to its strong triple bond.</p> Signup and view all the answers

<p>The metallic character of Group 15 elements increases as you move down the group.</p> Signup and view all the answers

<p>Nitrogen can exhibit oxidation states of -3 to +5.</p> Signup and view all the answers

<p>Nitrogen is distinct due to its smaller atomic radius, higher electronegativity, and the absence of d orbitals.</p> Signup and view all the answers

<p>It changes its packing arrangement to form β-sulphur (β-S8).</p> Signup and view all the answers

<p>Rhombic and monoclinic sulfur.</p> Signup and view all the answers

<p>Below 95 °C.</p> Signup and view all the answers

<p>By pouring melted sulfur into water and rapidly cooling it.</p> Signup and view all the answers

<p>Water is amphiprotic, acting as both an acid and a base.</p> Signup and view all the answers

<p>It has a bent molecular shape with a bond angle of 94.8° for H-O-O.</p> Signup and view all the answers

<p>It can act as both an oxidizing agent and a reducing agent.</p> Signup and view all the answers

<p>Extensive hydrogen bonding.</p> Signup and view all the answers

<p>Ammonia (NH3) and hydronium ion (H3O+).</p> Signup and view all the answers

<p>Sodium chloride (NaCl), ammonia (NH3), and water (H2O).</p> Signup and view all the answers

<p>Nitrogen gas (N2) and hydrochloric acid (HCl) are produced.</p> Signup and view all the answers

<p>It is used as a water disinfecting agent and produces ammonia (NH3) and hypochlorous acid (HOCl).</p> Signup and view all the answers

<p>A white smoke of solid ammonium chloride (NH4Cl).</p> Signup and view all the answers

<p>Ammonia (NH3), carbon dioxide (CO2), and water (H2O).</p> Signup and view all the answers

<p>Nitrous oxide (N2O) and water (H2O).</p> Signup and view all the answers

<p>The atomic radius increases due to greater electron repulsion as electrons are paired in the d orbitals.</p> Signup and view all the answers

<p>Sodium amide (NaNH2) and hydrogen gas (H2).</p> Signup and view all the answers

<p>Sc produces only Sc3+ ions, and Zn produces only +2 ions because they do not have partially filled d orbitals.</p> Signup and view all the answers

<p>They can exhibit multiple oxidation states due to varying numbers of d electrons participating in bonding.</p> Signup and view all the answers

<p>Electrons in the 4s orbital experience a lesser effective nuclear charge than those in the 3d orbital, leading to their removal first during ionization.</p> Signup and view all the answers

<p>Titanium commonly occurs as FeTiO3 (Ilmenite) and TiO2 (Rutile).</p> Signup and view all the answers

<p>The maximum possible oxidation state is the sum of all 4s and 3d electrons.</p> Signup and view all the answers

<p>Cr+ is rare and unstable because of its 3d54s1 configuration, making the formation of this oxidation state energetically unfavorable.</p> Signup and view all the answers

<p>As more 3d electrons are filled, their energy levels increase, making them harder to remove due to increased nuclear charge.</p> Signup and view all the answers