AQA AS Chemistry C9 The Alkaline Earth Metal Kerboodle

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9.1 The Physical And Chemical Properties Of Group 2 AQA AS Chemistry C9 The Alkaline Earth Metal Kerboodle Answers

1.Ans-

1. a) +2
2. b) This is because all the elements of group 2 loose two outer-s electrons while forming the compounds.
3. Ans-It becomes easier to for +2 ions on going down the group 2 as the size of atoms increases due to addition of completely filled shells on moving downwards.Due to this the nuclear pull experienced by the electrons decreases and hence it becomes easier to remove them.

3.Ans- This is a redox reaction because calcium is oxidized as it loses electrons and its oxidation state goes from 0 to +2 and chlorine is reduced as it gains electron and goes from oxidation state 0 to -1.

4. Ans- Ca + 2H₂0 -> Ca(OH)₂ + H₂ (Ca goes from 0 to +2. H from +1 to 0).
5. Ans- a. Strontium will react with water more vigorously as compared to Calcium as on moving down the group the reactivity increases.
6. Strontium will react less vigorously as compared to barium as it lies above it and it can be oxidized less easily as compared to barium.
7. Ans-
8. Radium hydroxide will be more soluble in comparison to the elements that lie above it in the group as on moving down the group the solubility of hydroxides increases.
9. Radium Sulfate will be less soluble as compared to the elements that lie above it as on moving down the group the solubility of sulfates decreases.

Practice Questions:

1.Ans- The melting point of Group 2 elements decreases on going down the group that is from Ca to Ba as the strength of metallic bonding decreases. 2.Ans- The solubility of the hydroxides increases on moving down the group while the solubility of sulfates decreases on moving down the group. Sodium sulfate and sodium nitrate can be distinguished using solution of barium chloride as in case of sodium sulfate this would generate a white insoluble ppt while there would be no such observation in case of sodium nitrate. Na₂SO₄ + BaCl₂ -> 2NaCl + BaSO₄(ppt) 3.Ans-

1. From Mg to Ba the solubility of hydroxides increases on moving down the group while the solubilities of sulfates decreases on moving down the group.
2. The presence of sulfate ions in an aqueous solution can be tested using barium ions since it forms a white insoluble ppt of Barium sulphate.Magnesium chloride and magnesium sulfate can also be distinguished using this test as in case of Magnesium sulfate a white ppt will be obtained. MgSO₄ + BaCl₂ -> BaSO₄ + MgCl₂
3. On moving down the group the reactivity of elements with water increases.

Ba(s) + 2H₂O (g) ->  Ba(OH)₂ (aq)  + H₂ (g) 4.Ans-

1. It works as a natural antacid and is used to treat gastrointestinal ailments such as heartburn and indigestion.
2. The reaction decreases with decrease in temperature because with decreasing temperature the kinetic energy also decreases.There is less kinetic energy for particles to move therefore less collisions, and therefore reaction rate decreases
3. i) Strontium has a higher melting point than barium because on moving down the group the strength of metallic bonding decreases therefore metallic bonding in strontium is stronger than that in barium
4. ii) The magnesium sulfate is SOLUBLE i.e it forms a solution as it get dissolves therefore the excess of magnesium used in the extraction can be removed by reacting it with dilute sulfuric acid to form magnesium sulfate.

5.Ans–

1. i)increases ii)decreases iii) increases
2. Calcium has a higher melting point than strontium because the metallic bonding is stronger in its case due to higher nuclear attraction
3. i)Sulfuric acid should not be used to identify barium chloride because both barium sulfate and barium chloride forms a similar insoluble white precipitate.
4. ii) BaCl₂ + SO₄ ^2- -> BaSO₄ +Cl₂

6.Ans-

1. Al –> Al⁺ + e^–
2. First,second
3. The first ionization energy of sulfur is less than that of phosphorus because it has paired electrons and there exists force of repulsion between them hence it is easier to remove them.
4. Neon has the highest first ionization energy. 1s²,2s²,2p⁶
5. On moving down the group the ionization energy decreases from beryllium to barium this is because with increase in size the nuclear attraction experienced by the outer electrons decreases.

7.Ans-

1. i) Ba(s) + 2H₂O (g) -> Ba(OH)₂ (aq)  + H₂ (g)

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