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SS2: CHEMISTRY - 1ST TERM

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  1. Periodicity and Periodic Table I | Week 1
    5 Topics
    |
    1 Quiz
  2. Quantum Numbers Orbitals & Electrical Structure | Week 2
    6 Topics
    |
    1 Quiz
  3. Periodicity and Periodic Table II | Week 3
    12 Topics
    |
    1 Quiz
  4. Periodicity and Periodic Properties III | Week 4
    11 Topics
    |
    1 Quiz
  5. Periodicity and Periodic Properties IV | Week 5
    5 Topics
    |
    1 Quiz
  6. Mass-Volume Relationship in Reaction | Week 6
    8 Topics
    |
    1 Quiz
  7. Types of Reactions: Oxidation and Reduction | Week 7 & 8
    7 Topics
    |
    1 Quiz
  8. Oxidation – Reduction Reaction II | Week 9
    3 Topics
    |
    1 Quiz
  9. Electrode Potential and Electrochemical Cells I | Week 10
    6 Topics
    |
    1 Quiz
  10. Electrode Potential and Electrochemical Cells II | Week 11
    5 Topics
    |
    1 Quiz
  11. Electrolysis I | Week 12
    8 Topics
    |
    1 Quiz
  12. Electrolysis II | Week 13
    8 Topics
    |
    1 Quiz
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Topic Content:

  • Group II Elements

Beryllium – 4Be → 2, 2

Magnesium – 12Mg → 2, 8, 2

Calcium – 20Ca → 2, 8, 8, 2

Group II elements include beryllium, magnesium, calcium, strontium, barium, and radium. Group II elements constitute the second most reactive group of metals. They are alkaline earth metals. They are divalent elements.

Mg → Mg2+ + 2e

Ca → Ca2+ + 2e-     

They are electron donors and form electrovalent compounds. They are strong reducing agents. They are also good conductors of electricity.

Magnesium reacts with steam to liberate hydrogen and form magnesium oxide.

Mg[s] + H2O[g] → MgO[s] + H2[g]

Calcium reacts slowly with cold water to liberate hydrogen and form hydroxide

Ca[s] + 2H2O[l] → Ca[OH]2[aq] + H2[g] 

Magnesium oxide is insoluble in water. But calcium oxide dissolves sparingly in water to form a calcium hydroxide solution. 

CaO[s] + H2O[l] → Ca[OH]2[aq]

Their trioxonitrate[V] salts decompose on heating to give oxides, oxygen, and nitrogen[IV] oxide gas

\( \scriptsize 2Mg(NO_{3})_{2(s)} \overset{heat}{\rightarrow} 2MgO_{(s)} + O_{2(g)} + 4NO_{2(g)}\)

Their trioxocarbonates [IV] decompose on heating to give the oxides and carbon[IV] oxide. They are insoluble in water.  

\( \scriptsize MgCO_{3(s)} \overset{heat}{\rightarrow} MgO_{(s)} + CO_{2(g)} \)

\( \scriptsize CaCO_{3(s)} \overset{heat}{\rightarrow} CaO_{(s)} + CO_{2(s)} \)