Here's why:
* Nucleus: The nucleus, containing protons and neutrons, is extremely dense and tiny compared to the overall size of the atom. It accounts for almost all of the atom's mass but only a negligible portion of its volume.
* Electron Cloud: Electrons, though much lighter than protons and neutrons, occupy a much larger volume. They don't orbit the nucleus in defined paths like planets around a star. Instead, they exist in a probability cloud, known as the electron cloud. This cloud is where you're most likely to find an electron at any given time.
Therefore, the electron cloud's vast expanse, not the nucleus, dominates the overall volume of an atom.
