Position of Hydrogen in Periodic Table - UNSOLVED PRACTICE SET
Chapter: Hydrogen | Topic: Position of Hydrogen in Periodic Table
POSITION OF HYDROGEN IN PERIODIC TABLE - UNSOLVED PRACTICE SET
Topic: Position of Hydrogen in Periodic Table
Multiple Choice Questions
Q1. Hydrogen is placed in Group 1 of the Periodic Table primarily because it:
- Is a metal like sodium and potassium
- Has one electron in its outermost shell
- Forms only positive ions like alkali metals
- Has a completely filled K-shell
Q2. Which property of hydrogen is similar to halogens (Group 17)?
- It forms basic oxides
- It exists as a diatomic molecule (H₂)
- It has one electron less than the nearest noble gas
- It forms ionic compounds only with metals
Q3. Hydrogen can gain one electron to achieve the helium configuration. This property makes it similar to:
- Alkali metals
- Halogens
- Noble gases
- Alkaline earth metals
Q4. The ionisation enthalpy of hydrogen (1312 kJ/mol) is much closer to that of:
- Sodium (496 kJ/mol)
- Chlorine (1256 kJ/mol)
- Lithium (520 kJ/mol)
- Fluorine (1681 kJ/mol)
Q5. Why can't hydrogen be placed in Group 14 despite having a half-filled outer shell?
- Because it doesn't form four bonds like carbon
- Because it doesn't have a penultimate shell
- Because its chemistry is completely different from Group 14 elements
- All of the above
Q6. In the modern Periodic Table, hydrogen is shown separately at the top because:
- It is the lightest element
- Its properties are unique and don't match any single group perfectly
- It was discovered first
- It is a noble gas
Short Answer Questions
Q7. Mention two properties of hydrogen that are similar to alkali metals and two properties that are similar to halogens.
Q8. Why is hydrogen considered a unique element that cannot be assigned a fixed position in the Periodic Table? Give any two reasons.
Q9. Compare the electronic configuration of hydrogen (1s¹) with that of sodium ([Ne] 3s¹) and chlorine ([Ne] 3s²3p⁵). What does this tell you about hydrogen's position?
Q10. Hydrogen forms H⁺ ions in aqueous solution like alkali metals, but also forms H⁻ ions with highly electropositive metals. What does this dual nature suggest about its position?
Q11. The atomic radius of hydrogen (37 pm) is much smaller than that of lithium (152 pm) but closer to fluorine (72 pm). What conclusion can you draw from this regarding hydrogen's placement?
Q12. Your teacher asks you to justify why hydrogen is sometimes placed above both Group 1 and Group 17 in some Periodic Tables. What would be your argument?
Long Answer Questions
Q13. Discuss in detail why hydrogen resembles both alkali metals and halogens. Illustrate your answer with at least three properties for each group comparison. Why do you think no single position completely satisfies hydrogen's nature?
Q14. Analyse the position of hydrogen in the Periodic Table by comparing:
(a) Its electronic configuration with Group 1, Group 17, and Group 14 elements
(b) Its ionisation enthalpy with these groups
(c) Its electronegativity (2.1 on Pauling scale) and what it implies
Conclude with your opinion on the most appropriate position for hydrogen.
Q15. Some modern Periodic Tables show hydrogen floating between Group 1 and Group 17. Explain the rationale behind this representation. Also, discuss why placing hydrogen in Group 1 is more common in NCERT textbooks despite its limitations.
Numerical / Application-Based Problems
Q16. The first ionisation enthalpy of hydrogen is 1312 kJ/mol. The first ionisation enthalpies of Li, Na, K, F, and Cl are 520, 496, 419, 1681, and 1256 kJ/mol respectively.
(a) Calculate the average ionisation enthalpy of alkali metals (Li, Na, K).
(b) Calculate the average ionisation enthalpy of halogens (F, Cl).
(c) Based on these averages, which group does hydrogen's ionisation enthalpy (1312 kJ/mol) align more closely with? Show your working.
Q17. The electronegativity values on the Pauling scale are: H = 2.1, Li = 1.0, Na = 0.9, F = 4.0, Cl = 3.0, C = 2.5.
(a) Find the difference in electronegativity between H and Li, and between H and F.
(b) Which difference is smaller, and what does this suggest about hydrogen's chemical behaviour?
(c) Why is electronegativity alone not sufficient to fix hydrogen's position?
Q18. In a classroom debate, Team A argues hydrogen should be in Group 1, while Team B argues for Group 17. As the judge, you must award points based on evidence:
(a) List two pieces of evidence supporting Team A.
(b) List two pieces of evidence supporting Team B.
(c) Give your final verdict with one reason why hydrogen deserves a special position.