Group 2 - General Properties and Trends - UNSOLVED PRACTICE SET
Chapter: s-Block Elements Alkali and Alkaline Earth Metals | Topic: Group 2 General Properties and Trends
GROUP 2 - GENERAL PROPERTIES AND TRENDS - UNSOLVED PRACTICE SET
Topic: Group 2 General Properties and Trends
Multiple Choice Questions
Q1. The general electronic configuration of alkaline earth metals is:
- ns¹
- ns²
- ns²np¹
- ns²np⁶
Q2. Among the alkaline earth metals, which has the highest first ionisation enthalpy?
- Be
- Mg
- Ca
- Ba
Q3. The atomic radius of alkaline earth metals is smaller than the corresponding alkali metals because:
- They have fewer electrons
- They have a higher nuclear charge and the electrons are pulled closer
- They have completely filled d-orbitals
- They form cations more easily
Q4. Which alkaline earth metal does NOT react with water under normal conditions?
- Mg
- Ca
- Sr
- Ba
Q5. The reducing power of alkaline earth metals increases down the group because:
- Ionisation enthalpy decreases
- Atomic size decreases
- Electronegativity increases
- Lattice energy increases
Q6. Beryllium and magnesium are rendered passive by:
- Dilute HCl
- Concentrated nitric acid
- Dilute NaOH
- Distilled watern
Short Answer Questions
Q7. Compare the first and second ionisation enthalpies of alkaline earth metals with those of alkali metals. Why are the second ionisation enthalpies of alkaline earth metals lower than expected?
Q8. Why are alkaline earth metals harder and have higher melting points than alkali metals? Explain in terms of metallic bonding.
Q9. Write balanced chemical equations for the reaction of calcium with:
(a) Water
(b) Dilute hydrochloric acid
(c) Oxygen
Q10. Explain why beryllium compounds are largely covalent, while compounds of other alkaline earth metals are ionic.
Q11. Your school chemistry lab has samples of magnesium ribbon and calcium metal. Suggest one simple test to distinguish between them based on their reaction with cold water.
Q12. Why do alkaline earth metals form +2 oxidation state compounds predominantly? What is the significance of the inert pair effect in this context?
Long Answer Questions
Q13. Discuss the general characteristics of alkaline earth metals (Group 2) with respect to:
(a) Electronic configuration and atomic radius trends
(b) Ionisation enthalpy and its comparison with Group 1
(c) Electronegativity and metallic character
(d) Reaction with oxygen, water, and acids
Illustrate with relevant chemical equations.
Q14. Compare and contrast the properties of alkali metals (Group 1) and alkaline earth metals (Group 2) under the following headings:
(a) Physical properties (hardness, melting point, density)
(b) Chemical reactivity with water and oxygen
(c) Nature of oxides and hydroxides formed
(d) Solubility of sulphates and carbonates
Give reasons for the observed differences.
Q15. Magnesium and calcium are essential elements in Indian agriculture and daily life. Discuss:
(a) Why magnesium is called the "central atom" of chlorophyll and its role in photosynthesis
(b) Why calcium is added to cement and concrete used in construction across India
(c) The use of calcium in water treatment plants to remove impurities
(d) Why dolomite (CaMg(CO₃)₂) is mined extensively in India and its uses
Numerical / Application-Based Problems
Q16. The first ionisation enthalpies of Be, Mg, Ca, Sr, and Ba are 899, 737, 590, 549, and 503 kJ/mol respectively. The second ionisation enthalpies are 1757, 1450, 1145, 1064, and 965 kJ/mol respectively.
(a) Calculate the sum of first and second ionisation enthalpies for each metal.
(b) Arrange the metals in increasing order of total energy required to form M²⁺ ions.
(c) Explain why beryllium requires the most energy despite being the smallest.
Q17. A 2.0 g sample of an alkaline earth metal reacts completely with water to produce 1.12 L of hydrogen gas at STP.
(a) Write the general reaction of an alkaline earth metal (M) with water.
(b) Calculate the equivalent mass of the metal.
(c) Identify the metal from the given data.
[Given: Atomic masses: Be = 9, Mg = 24, Ca = 40, Sr = 88, Ba = 137; Molar volume at STP = 22.4 L]
Q18. In the extraction of magnesium from sea water, 1000 L of sea water containing 1.3 g of Mg²⁺ per litre is processed.
(a) Calculate the total mass of magnesium ions present in 1000 L of sea water.
(b) If the extraction process is 80% efficient, calculate the mass of pure magnesium obtained.
(c) If magnesium is sold at ₹ 250 per kg, calculate the value of magnesium extracted from this batch.
[Given: Atomic mass of Mg = 24]