What is the Greek etymology for "-on" in words like "proton" and "neutron"? [closed]

Google says "proton" is from "protos" and "-on" ("first" + "being"), or "πρῶτος" and "?". What is the "-on" in Greek, is it "ὤν" or "ἐν" or something?

Solution 1:

-on, from ion, Greek present participle of ienai (go)

Electron:

coined 1891 by Irish physicist George J. Stoney (1826-1911) from electric + -on, as in ion.

ion (n.):

1834, introduced by English physicist and chemist Michael Faraday (suggested by the Rev. William Whewell, English polymath), coined from Greek ion, neuter present participle of ienai "go," from PIE root *ei- "to go." So called because ions move toward the electrode of opposite charge.

(Etymonline)

Solution 2:

Here's the Oxford English Dictionary's etymology for the ending -on:

-on (in electron n.2, itself after earlier ion n.), reinforced in both senses by -ον as a termination of Greek neuter nouns and adjectives and their derivatives, and (especially in sense 2) perhaps by ancient Greek ὄν being (compare -ont comb. form).

Context:

• "Sense 2" is in words like chronon, virion, and codon which are "entities conceived of as discrete or basic units".
• -ont is used in words like planont.