P

Proton

¹₁H (proton, p)
Quick Reference
Formula / Notation¹₁H (proton, p)
Also Known AsHydrogen ion (H⁺), hydron, proton (subatomic), ¹H nucleus

What is Proton?

A subatomic particle in the nucleus with a positive charge of +1.6 × 10⁻¹⁹ coulombs and a mass of 1.673 × 10⁻²⁷ kg. The number of protons (atomic number) defines the element. In acid-base chemistry, a proton is equivalent to a hydrogen ion (H⁺).

Formula & Notation

¹₁H (proton, p)

Other Names / Synonyms: Hydrogen ion (H⁺), hydron, proton (subatomic), ¹H nucleus

Properties & Characteristics

The proton is a subatomic particle with a positive charge of +1 (in units of elementary charge e), a rest mass of 1.00728 amu (938.3 MeV/c²), and quark composition (uud). It is a constituent of all atomic nuclei (the number of protons = atomic number Z). In chemistry, "proton" often refers to the hydrogen ion H⁺ (a bare proton in the gas phase, or solvated hydronium H₃O⁺ in water). Proton transfer is the basis of Brønsted-Lowry acid-base chemistry.

Uses & Applications

Protons are used in: nuclear reactions (proton beams in particle accelerators), proton therapy for cancer (high-LET radiation deposits energy precisely at the Bragg peak), proton NMR (¹H spin = ½, used in NMR spectroscopy), fuel cells (proton exchange membrane, PEM, where protons migrate through Nafion membrane), and as the fundamental unit of acid-base chemistry.

Safety Information

High-energy proton beams (particle therapy, accelerators) cause ionising radiation injury. Proton NMR instruments with superconducting magnets present strong magnetic field hazards. In chemistry, "protons" as H⁺ in concentrated strong acids are the source of corrosivity — high [H₃O⁺] causes severe burns.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Proton
Formula ¹₁H (proton, p)
Synonyms Hydrogen ion (H⁺), hydron, proton (subatomic), ¹H nucleus

Frequently Asked Questions

A subatomic particle in the nucleus with a positive charge of +1.6 × 10⁻¹⁹ coulombs and a mass of 1.673 × 10⁻²⁷ kg. The number of protons (atomic number) defines the element. In acid-base chemistry, a proton is equivalent to a hydrogen ion (H⁺).

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