Summary

• Atom is the smallest particle of an element.
• Atom consists of proton, neutron and electron.
• Nucleus is the core of an atom where protons and neutrons reside.
• Nucleus is positively (+) charged.
• Proton are positively (+) charged.
• Neutrons has no electrical charge.
• Electrons are negatively (-) charged.
• Protons and neutrons have nearly same amount of mass.
• Mass of proton is approximately 1836 times that of the electron.
• In an atom, number of protons = number of neutrons = atomic number.
• Atomic mass = number of protons + number of neutrons.