Constants & Units · constant
Electron mass
m_e = 9.109 383 7139(28) × 10⁻³¹ kg
- Unit
- kg
- Value
- 9.109 383 7139(28) × 10⁻³¹
- Exact
- no
- Note
- 1/1836 of the proton — light enough to be quantum-mechanically smeared across an atom.
- Symbol
- m_e
- Category
- Atomic & nuclear
- Numeric
- 9.1093837139e-31
- Uncertainty
- ±3.1 × 10⁻¹⁰ relative
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