What is the nucleus for Class 9?

The nucleus is the central, dense part of an atom where all the positive charge and almost all the mass of the atom are concentrated.

• It is made up of protons (positively charged particles) and neutrons (neutral particles), together called nucleons.
• The nucleus is very small in size compared to the overall atom but contains nearly the whole mass of the atom.
• The electrons revolve around the nucleus in specific orbits or shells.

In short, for Class 9: The nucleus is the tiny, dense core at the center of an atom containing protons and neutrons, which accounts for the atom’s mass and positive charge.