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NEET CHEMISTRYSome Basic Concepts of ChemistryEasy

Question

Which of the following contains the maximum number of atoms?

A

1 g of Mg(s)

B

1 g of O₂ (g)

C

1 g of Li(s)

D

1 g of Ag(s)

Step-by-Step Solution

  1. Principle: The number of atoms (NN) in a given mass (ww) of a substance is calculated using the mole concept: N=Moles×NA×AtomicityN = \text{Moles} \times N_A \times \text{Atomicity} N=wMolar Mass×NA×AtomicityN = \frac{w}{\text{Molar Mass}} \times N_A \times \text{Atomicity} Since the mass (ww) is constant (1 g) for all options, the number of atoms is inversely proportional to the atomic mass (or effective mass per atom).

  2. Calculations (using approximate atomic masses):

  • Option A (Mg): Atomic mass 24\approx 24 g/mol. NMg=124×1×NA0.04NAN_{Mg} = \frac{1}{24} \times 1 \times N_A \approx 0.04 N_A
  • Option B (O2O_2): Molecular mass = 32 g/mol. Atomicity = 2. NO=132×2×NA=116NA0.06NAN_{O} = \frac{1}{32} \times 2 \times N_A = \frac{1}{16} N_A \approx 0.06 N_A
  • Option C (Li): Atomic mass 7\approx 7 g/mol. NLi=17×1×NA0.14NAN_{Li} = \frac{1}{7} \times 1 \times N_A \approx 0.14 N_A
  • Option D (Ag): Atomic mass 108\approx 108 g/mol. NAg=1108×1×NA0.009NAN_{Ag} = \frac{1}{108} \times 1 \times N_A \approx 0.009 N_A
  1. Conclusion: Lithium (Li) has the lowest atomic mass among the given monoatomic solids and the effective atomic mass of oxygen in O2O_2 (16). Therefore, 1 g of Li contains the maximum number of atoms .

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Some Basic Concepts of Chemistry. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYSome Basic Concepts of Chemistryfollowingcontainsmaximumnumber

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