S-Block Elements Quiz
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Questions and Answers

What is the chemical formula for the compound produced when calcium oxide reacts with carbon dioxide?

  • CaSO4
  • CaCO3 (correct)
  • Ca(OH)2
  • CaCl2

    • Which of the following reagents can be used to convert calcium oxide into calcium chloride?

  • P4O10
  • SiO2
  • SO2
  • HCl (correct)

    • What is the temperature range for the preparation of plaster of paris from gypsum?

  • 120-140°C (correct)
  • 140-160°C
  • 160-180°C
  • 100-120°C

    • What is the chemical formula of the compound that is formed upon further dehydration of plaster of paris at a temperature higher than 140°C?

    <p>CaSO4</p> Signup and view all the answers

    What is the product of the reaction between calcium chloride and sodium carbonate?

    <p>CaCO3</p> Signup and view all the answers

    Which of the following is a property of gypsum?

    <p>It is a white crystalline solid.</p> Signup and view all the answers

    What is the effect of sodium chloride on the setting of plaster of paris?

    <p>Sodium chloride increases the setting time.</p> Signup and view all the answers

    Which of the following reactions is NOT a method for the preparation of calcium sulphate?

    <p>CaO + SO2 → CaSO3</p> Signup and view all the answers

    Which of the following alkaline earth metal carbonates is the most thermally stable?

    <p>BaCO3</p> Signup and view all the answers

    Why is BeCO3 stored in a CO2 atmosphere?

    <p>To prevent decomposition</p> Signup and view all the answers

    Which of the following best explains the trend in ionization enthalpy across the alkali metals (Li > Na > K > Rb)?

    <p>Increasing atomic radius</p> Signup and view all the answers

    The low solubility of LiF in water is primarily attributed to which factor?

    <p>Low lattice enthalpy of lithium fluoride</p> Signup and view all the answers

    Which of the following Group 2 metal hydroxides is amphoteric and soluble in sodium hydroxide?

    <p>Be(OH)2</p> Signup and view all the answers

    Which of the following statements best explains the observation that BeCO3 is less stable than BaCO3?

    <p>Be is less electropositive than Ba.</p> Signup and view all the answers

    Which of the following factors is responsible for the decreasing ionization enthalpy trend down the alkali metal group?

    <p>Increased shielding effect</p> Signup and view all the answers

    Which of the following statements accurately describes the relationship between lattice enthalpy and hydration enthalpy in determining the solubility of metal halides?

    <p>Solubility is higher when hydration enthalpy is greater than lattice enthalpy.</p> Signup and view all the answers

    What is the product formed when gypsum is heated at 120°C?

    <p>Plaster of Paris</p> Signup and view all the answers

    What happens to plaster of Paris when heated to 200°C?

    <p>It forms dead plaster</p> Signup and view all the answers

    Which term refers to the suspension of slaked lime in water?

    <p>Milk of lime</p> Signup and view all the answers

    Which of the following does not form hydride by direct heating with dihydrogen?

    <p>Beryllium (Be)</p> Signup and view all the answers

    What is the formula for soda ash?

    <p>Na2CO3</p> Signup and view all the answers

    What is the product formed when magnesium reacts with water?

    <p>MgO and H2</p> Signup and view all the answers

    Which alkaline earth metal is amphoteric in nature?

    <p>Beryllium</p> Signup and view all the answers

    Among the alkaline earth metals, which one does not combine with hydrogen to form a hydride under heating?

    <p>Beryllium</p> Signup and view all the answers

    What reaction takes place when calcium nitride reacts with water?

    <p>Ca3N2 + 6H2O → 3Ca(OH)2 + 2NH3</p> Signup and view all the answers

    Which of the following is the correct thermal decomposition reaction to prepare BeCl2?

    <p>BeO + C + Cl2 → BeCl2 + CO</p> Signup and view all the answers

    What is produced when calcium nitrate is heated?

    <p>CaO, NO2, and O2</p> Signup and view all the answers

    Which compound is responsible for the activity of various enzymes including those in glycolysis?

    <p>Magnesium</p> Signup and view all the answers

    What is the nature of the hydroxides of alkaline earth metals as the atomic number increases?

    <p>Increasingly basic</p> Signup and view all the answers

    What is the main product when quick lime reacts with silica?

    <p>Calcium silicate</p> Signup and view all the answers

    Which statement about beryllium is true regarding its reactivity?

    <p>It is less reactive than other alkaline earth metals.</p> Signup and view all the answers

    Which of the following is NOT a component of Portland cement?

    <p>Potassium sulfate</p> Signup and view all the answers

    In the vapor phase, BeCl2 tends to form a specific structural form. What is that form?

    <p>Chloro-bridged dimer</p> Signup and view all the answers

    What is the biological role of calcium in plants?

    <p>Stabilizes cell membranes</p> Signup and view all the answers

    What is produced when magnesium is burnt in air?

    <p>MgO</p> Signup and view all the answers

    How does magnesium influence ATP synthesis in the cell?

    <p>It serves as a cofactor</p> Signup and view all the answers

    What happens to calcium sulfate dihydrate when heated?

    <p>It becomes calcium sulfate anhydrate</p> Signup and view all the answers

    Why is the Solvay process unsuitable for preparing potassium carbonate?

    <p>Potassium carbonate is too soluble in water, preventing it from precipitating.</p> Signup and view all the answers

    Among the alkali metals, which one reacts LEAST vigorously with water?

    <p>Lithium (Li)</p> Signup and view all the answers

    Which factor MOST significantly contributes to lithium's high reducing power in aqueous solutions?

    <p>Hydration enthalpy</p> Signup and view all the answers

    Which of the following statements accurately explains the difference in thermal stability between lithium carbonate (Li₂CO₃) and sodium carbonate (Na₂CO₃)?

    <p>Li₂CO₃ is more covalent than Na₂CO₃, resulting in weaker bonds and lower thermal stability.</p> Signup and view all the answers

    What is the primary reason for the decomposition of metal carbonates upon heating?

    <p>All of the above.</p> Signup and view all the answers

    Which metal carbonate is MOST stable thermally?

    <p>Caesium carbonate (Cs₂CO₃)</p> Signup and view all the answers

    In which of the following options does the metal carbonate decompose at a higher temperature than lithium carbonate (Li₂CO₃)?

    <p>All of the above.</p> Signup and view all the answers

    What is the main reason for the difference in reactivity between lithium and the other alkali metals with water?

    <p>Difference in melting point.</p> Signup and view all the answers

    Signup and view all the answers

    Study Notes

    S-Block Elements

    • Alkali Metals are Group 1 elements
    • Alkali earth metals are Group 2 elements
    • The last electron enters the s-orbitals
    • Two groups (1 and 2) belong to the s-block due to the s-orbitals accommodating only two electrons.

    Electronic Configuration

    • Group 1 elements have one electron in their valence shell
    • Groups 1 and 2 elements are collectively known as alkali metals
    • The elements form strong alkalis when their oxides and hydroxides form

    Properties of Alkali Metals

    • Electronic configuration: ns¹
    • Physical state: Silvery white, soft, and light
    • Atomic and ionic radii, volume: Li < Na < K < Rb < Cs < Fr
    • Density: Low densities, increases from Li to Cs
    • Melting point and boiling points: Decreases from Li to Cs
    • Metallic character: Li < Na < K < Rb < Cs
    • Conductivity: Good conductors
    • Oxidation state: +1
    • Ionization enthalpy: Li > Na > K > Rb > Cs > Fr
    • Hydration of ions: Li⁺ > Na⁺ > K⁺ > Rb⁺ > Cs⁺ (Degree of Hydration)
    • Hydration Energy: Li⁺ > Na⁺ > K⁺ > Rb⁺ > Cs⁺
    • Photoelectric effect: Alkali metals (except Li) exhibit photoelectric effect. Potassium and Caesium are used in photoelectric cells due to low ionization enthalpy.

    Properties of Alkali Earth Metals

    • Electronic configuration: ns²
    • Atomic and ionic radii, volume: Be < Mg < Ca < Sr < Ba < Ra.
    • Density: Greater than alkali metals, irregular trend due to crystal structure
    • Melting point and boiling points: Decreases from Be to Ba
    • Metallic character: Be < Mg < Ca < Sr < Ba < Ra
    • Conductivity: Good conductors
    • Oxidation state: +2
    • Ionization enthalpy: Be > Mg > Ca > Sr > Ba > Ra
    • Hydration enthalpy: Be⁺² > Mg⁺² > Ca⁺² > Sr⁺² > Ba⁺² > Ra⁺² (Degree of Hydration, greater than alkali metals)
    • Flame Test: Beryllium and Magnesium do not impart color to the flame.
    • Reactivity towards water: All alkali metals readily react with water, forming corresponding hydroxides.

    Chemical Properties of Alkali Metals

    • Reactivity towards air: They vigorously react with oxygen (O2) at room temperature, forming oxides like Li2O, Na2O2 (peroxides)
    • Reactivity towards water: Highly reactive; the reaction becomes more vigorous down the group.
    • Reducing nature: Strong reducing agents (Li is more strongly reducing than others)
    • Solution in liquid ammonia: Dissolving alkali metals in liquid ammonia yields deep blue solutions.

    Photoelectric effect

    • Alkali metals readily emit electrons on exposure to light due to their low ionization enthalpy (Potassium and Caesium are commonly used in photoelectric cells)

    Important Compounds of Alkali Metals

    • Sodium Hydroxide (NaOH): Caustic soda, prepared by electrolysis of NaCl
    • Sodium Carbonate (Na2CO3): Washing soda, made by Solvay process

    Important Compounds of Alkali Earth Metals

    • Calcium Oxide (CaO): Quick Lime, produced by strongly heating limestone
    • Calcium Carbonate (CaCO3): Limestone, used for manufacturing quick lime

    Cement

    • A mixture of compounds, including oxides of calcium, silicon, aluminum, and iron
    • Compositions: CaO(50-60%), SiO2 (20-25%), Al2O3 (5-10%), MgO (1-3%), Fe2O3(1-2%)
    • Has a significant role in the production of concrete

    Biological Importance of Magnesium

    • Essential for the activity of many enzymes
    • A component of chlorophyll for photosynthesis
    • Important for ATP synthesis
    • Responsible for DNA stability
    • Maintains electrolyte balance

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    S-block Elements PDF

    Description

    Test your knowledge on the s-block elements of the periodic table. This quiz covers alkali metals and alkaline earth metals, exploring their properties, electronic configurations, and trends. Challenge yourself and see how well you understand these essential elements!

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