Usage - Pronoun-Antecedent Agreement. A pronoun is a word used to stand for (or take the place of) a noun. A word can refer to an earlier noun or pronoun in the sentence. Example:
A subatomic particle is a unit of matter or energy that's the fundamental makeup of all matter. According to modern atomic theory, an atom has a nucleus, which is its center, or core. The nucleus contains subatomic particles: protons and neutrons. Protons are positively-charged particles. Neutrons are neutral particles.
1. 1  a positively charged elementary particle that is a fundamental constituent of all atomic nuclei. It is the lightest and most stable baryon, having a charge equal in magnitude to that of the electron, a spin of Â½, and a mass of 1.673 Ã 10â 27 kg. Symbol: P.