Question:medium

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.

Updated On: Jan 21, 2026
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Solution and Explanation

Given:

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


(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


(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


Final Answers:

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

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