Question

The diameter of zinc atom is 2.6 Å. Calculate (a) radius of zinc atom in pm and (b) number of atoms present in a length of 1.6 cm if the zinc atoms are arranged side by side lengthwise.

Answer 1

Given:

Diameter of zinc atom = 2.6 Å
1 Å = 10⁻¹⁰ m
Length = 1.6 cm = 1.6 × 10⁻² m

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(a) Radius of zinc atom

Radius = Diameter / 2

Radius = 2.6 / 2 = 1.3 Å

1 Å = 100 pm

Radius = 1.3 × 100 = 130 pm

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(b) Number of atoms in 1.6 cm length

Diameter of one zinc atom = 2.6 Å = 2.6 × 10⁻¹⁰ m

Number of atoms = Total length / Diameter of one atom

Number of atoms = (1.6 × 10⁻²) / (2.6 × 10⁻¹⁰)

Number of atoms = 6.15 × 10⁷

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Final Answers:

(a) Radius of zinc atom = 130 pm
(b) Number of atoms in 1.6 cm = 6.15 × 10⁷