Question

The radius of the first orbit in a hydrogen atom is 0.53A° (1A°=10^-8cm).
Express in:
Cm

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Answer 1

Explanation:

0.53A°= 0.53(10^-8)cm

or 5.3×10^-9cm

Answer 2

Answer:

0.265A° or 0.026nm.

Explanation:

Radius of the nth orbit(rn) is directly proportional to n^2 and inversely proportional to Z.

For Hydrogen atom, rn= n^2× 0.53A° and for the first orbit r1= 0.53A° or 0.05 nm.

This is called Bohr Radius . For Helium atom Z=2. So r1= 0.53A° × (1/2) . So the answer is 0.265A° or 0.026nm.