# mass number

> number of heavy particles in the atomic nucleus

**Wikidata**: [Q101395](https://www.wikidata.org/wiki/Q101395)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Mass_number)  
**Source**: https://4ort.xyz/entity/mass-number


## References

1. [Source](https://goldbook.iupac.org/html/M/M03726.html)
2. Freebase Data Dumps. 2013
3. ISO 80000-10:2019 Quantities and units — Part 10: Atomic and nuclear physics
4. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)