1. Write the reactions of Group II A elements with water.

Group II A elements react with water to liberate hydrogen.  The reactivity increases from Be to Ra.  Be does not react with cold water or steam. Mg reacts with hot water liberating hydrogen.

  Mg+2H₂O → Mg(OH)₂ + H₂ ↑

Ca, Sr and Ba readily react with cold water to liberate hydrogen.

  M + 2H₂O → M(OH)₂ + H₂ ↑ (M = Ca, Sr, Fa)

2. What is the reaction of chlorine with alkaline earth metals?

  All the alkaline earth metals react with chlorine to form chlorides, MCl₂

   M + Cl₂ ↑ →  MCl₂ (M= alkaline earth metals).

3. How magnesium chloride prepared from magnesite?

  Magnesite (MgCO₃) is heated in the presence of air to 450^oC to give magnesium oxide.

     MgCO₃ → MgO + CO₂↑

  MgO is mixed with carbon powder and heated to 1000^oC in a flow of chlorine gas to give magnesium chloride (MgCl₂) and carbon monoxide (CO).

    MgO + Cl₂ + C → MgCl₂ + CO↑

4. Give the reactions of alkaline earth metals with oxygen.

 All the group II A elements burn in oxygen to form oxides.

 2M+O₂ → 2MO (M= alkaline earth metals)

 Barium forms peroxides with excess of oxygen.

    Ba + O₂   →  BaO₂

         (excess)    (Barium peroxide)

    Mg+ air →   MgO + Mg₃N₂.

5.How Beryllium hydride is prepared?

 Beryllium hydride (BeH₂) is prepared by reducing  BeCl₂ with  lithium aluminium hydride (LiAlH₄).

   2BeCl₂ +LiAlH₄ →  2BeH₂ +LiCl+ AlCl₃

6. Give the  reactions at anode and cathode during the electrolytic reactions  of magnesium chloride.

    At cathode,  magnesium  is obtained

     Mg²⁺ + 2e^-   →   Mg.

  At anode chlorine is liberated 

   2 Cl^- →  Cl₂+ 2e^-

  MgCl₂  →  Cl₂   +   Mg

                  (anode)  (cathode)

 Thus magnesium is obtained at cathode and chlorine is liberated at anode.

7. Give the reaction of alkaline earth metals with hydrogen.

 All the group II A elements except Be react with hydrogen to form hydrides.

  M+H₂ →  MH₂ (M= alkaline earth metals)

8.What is the trend of ionization energy in alkaline earth metals?

 As we go down from Be to Ra, the ionization energy decreases due to decrease in atomic radius. As the atomic size decreases, the attraction between the nucleus and valence electrons decreases. Hence it is easier to remove valence electrons.  This results in the decreasing trend in the ionization energy as we go down from Be to Ra.

9. Write  a short note on electronegativity of alkaline earth metals?

 The electronegativity of group IIA elements decreases from Be to Ra. As the  atomic size increases  from Be to Ra, the electronegativity  decreases.

10.Write the important ores of alkaline earth metals?