Rutherford's experiment on scattering of alpha particles showed for the first time that atom has: (a) Electrons (b) Protoris (c) Nucleus (d) Neutrons

The structure of an atom can be likened to a miniature solar system, with a dense nucleus at the core, analogous to the sun, and electrons orbiting around it like planets. This nucleus, incredibly tiny compared to the entire atom, contains the major portion of the atom's mass.

To put this in perspective, if an atom were the size of a football stadium, the nucleus would be no larger than a pea situated at the center field. Yet, this minuscule nucleus houses almost all of the atom's weight. Rutherford's gold foil experiment was pivotal in illustrating that the atom is mostly empty space, with electrons occupying the vast regions outside the nucleus. The revelation that an atom consisted of a central nucleus surrounded by a cloud of electrons reshaped our understanding of atomic structure and laid the groundwork for modern chemistry and physics.

Before the groundbreaking work of Ernest Rutherford, the atom was thought to be a 'plum pudding model,' with electrons embedded within a positive charge like plums within a pudding. This model was upended by the gold foil experiment that Rutherford conducted, which provided convincing evidence of a densely packed center of positive charge—a nucleus—within the atom.

Most alpha particles passed through the gold foil with no deflection, indicating a vast, empty space within the atom. However, some particles were deflected at severe angles, and a few even rebounded, suggesting a small, dense, positively charged center. Through meticulous analysis, Rutherford concluded that the core must contain the mass of the atom along with its positive charge, unveiling the nucleus's existence.

Subatomic particles are the building blocks of atoms, comprising electrons, protons, and neutrons. After the nucleus discovery, scientists recognized that the positively charged protons were situated in the nucleus, with the neutrons, discovered later by James Chadwick, laying the groundwork for the strong nuclear force that holds the nucleus together.

Electrons, identified by J.J. Thomson before Rutherford's experiment, were understood to be positioned outside the nucleus, creating a balance of charge within the atom. The behavior of these subatomic particles and their arrangements govern the entirety of chemical reactions and the properties of elements, making the discovery and understanding of these particles vital to advances in both physics and chemistry.