The radius of the first Bohr orbit of hydrogen is about:

The radius of the first Bohr orbit of…

Answer: 0.53 Å.

A 0.53 Å
B 1 Å
C 5.3 Å
D 0.053 Å

Correct answer: A. 0.53 Å

Explanation: The Bohr radius is approximately 0.53 ångström (5.3 × 10⁻¹¹ m).

Comparison of the Thomson model and the Rutherford model of the atom: in the Thomson plum pudding model alpha particles pass almost straight through a diffuse positive sphere, while in the Rutherford model a concentrated central nucleus deflects some alpha particles through large angles, with the lower panels showing the alpha particle source and gold foil and the observed result of wide-angle scattering

The Geiger–Marsden alpha-scattering result: a few alpha particles bounce back at large angles, which rules out Thomson’s diffuse model and demands a tiny, massive, positively charged nucleus. Image: Kurzon, CC BY 3.0, via Wikimedia Commons.

Concept context

Thomson's plum-pudding model, Rutherford's nuclear model from alpha-scattering, Bohr's postulates and hydrogen spectrum, spectral series (Lyman to Pfund), Rydberg formula, and limitations of each model.

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The radius of the first Bohr orbit of hydrogen is about:

Concept context

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