Final answer:
A proton is the particle within an atom that carries a positive charge and is found in the nucleus. It is significantly more massive than an electron and, along with neutrons, contributes to most of an atom's mass.
Step-by-step explanation:
The relatively large particle within an atom that carries a positive electrical charge and is found within an atomic nucleus is known as a proton. Protons, along with neutrons, form the nucleons of the nucleus. Protons have a mass of 1 atomic mass unit (amu), equivalent to 1.67 × 10-27 kilograms and carry a positive charge of +1.602 × 10−19 Coulombs (C). This charge is of the same magnitude but opposite in sign to the charge of an electron, which is −1.602 × 10−19 C. While electrons are much smaller in mass compared to protons (∼ 1836 times lighter), both are fundamental particles that carry electric charge; protons with positive charge and electrons with negative charge.