HARDMCQ SINGLENEET ChemistryPhysical ChemistryAtomic StructureIntro
[Manipal 2008] The radius of the nucleus of mass number A is given by r = 1.25 × 10⁻¹³ × A^(1/3) cm. The radius of the atom is 1.0 Å. For mass number A = 64, the fraction of atomic volume occupied by the nucleus is
0.1.0 × 10⁻³
1.5.0 × 10⁻⁵
2.2.5 × 10⁻²
3.1.25 × 10⁻¹³
Explanation
r_nucleus = 1.25 × 10⁻¹³ × (64)^(1/3) = 1.25 × 10⁻¹³ × 4 = 5 × 10⁻¹³ cm. r_atom = 10⁻⁸ cm. Fraction = (r_nucleus/r_atom)³ = (5×10⁻¹³/10⁻⁸)³ = (5×10⁻⁵)³ = 1.25 × 10⁻¹³
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