Electron
From Memory Alpha, the free Star Trek reference.
An electron is a subatomic particle that orbits around the nucleus of an atom. There is usually the same number as the number of protons; if not then the atom is known as an ion. Electrons have a mass of almost nothing compared to protons and neutrons, and have a negative charge. The antimatter equivalent of an electron is a positron.
Chlorophyll gives off high energy electrons that are picked up by other molecules, as Julian Bashir told Goran'Agar in 2372 giving Chief Miles O'Brien time to create a plasma charge. (DS9: "Hippocratic Oath")
A message communicated to Counselor Troi contained the phrase: "One moon circles." Upon further investigation, with the assistance of Data, it was determined that the phrase was in reference to the hydrogen atom, where "one electron circles one proton." (TNG: "Night Terrors")
