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To convert Bohr radii to meters: multiply by 5.29177210903 × 10⁻¹¹.
a₀ = ℏ/(mec α) = 4πε₀ℏ²/(mee²) ≈ 5.29177 × 10⁻¹¹ m, where α is the fine-structure constant.
For example, 1 Bohr Radius (a₀) = 52.91772109 Picometer (pm).
| Bohr Radius (a₀) | Picometer (pm) |
|---|---|
| 0.1 | 5.291772109 |
| 0.5 | 26.45886055 |
| 1 | 52.91772109 |
| 2 | 105.8354422 |
| 5 | 264.5886055 |
| 10 | 529.1772109 |
| 25 | 1322.943027 |
| 50 | 2645.886055 |
| 100 | 5291.772109 |
| 500 | 26458.86055 |
| 1000 | 52917.72109 |
The Bohr radius is the most probable distance between the nucleus and the electron in a ground-state hydrogen atom, approximately 5.292 × 10⁻¹¹ meters.
a₀ = ℏ/(mec α) = 4πε₀ℏ²/(mee²) ≈ 5.29177 × 10⁻¹¹ m, where α is the fine-structure constant.
To convert Bohr radii to meters: multiply by 5.29177210903 × 10⁻¹¹.
Sets the characteristic scale for atomic sizes. Most atoms have radii of 1–3 Bohr radii.
The Bohr radius gives atoms their characteristic size of ~1 Å (10⁻¹⁰ m), explaining why matter has the volume it does.
Confusing Bohr radius with atomic radius — the Bohr radius is specific to hydrogen; other atoms have different sizes.
The Bohr radius tells you 'how big atoms are' — about 0.5 angstroms. It's the atomic analog of a ruler for atomic-scale physics.
The picometer is a unit of length equal to 10⁻¹² meters, or one trillionth of a meter.
1 pm = 10⁻¹² m = 0.01 Å = 1,000 fm. One nanometer equals 1,000 picometers.
To convert pm to meters: multiply by 10⁻¹². To convert pm to angstroms: divide by 100.
Expressing covalent bond lengths (e.g., C–C bond ≈ 154 pm), atomic radii, and crystal lattice spacings.
The hydrogen atom has a radius of about 53 pm (the Bohr radius), while a carbon-carbon single bond is about 154 pm long.
Mixing up picometers and nanometers — remember 1 nm = 1,000 pm. Some sources still use the deprecated angstrom.
Think of pm as the natural unit for atoms: most atomic radii fall between 30 pm and 300 pm.



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