Final answer:
The Rutherford atom, or Rutherford's planetary model, is an atomic model proposed by Ernest Rutherford, featuring a dense, positively charged nucleus surrounded by orbiting electrons, analogous to a planetary system.
Step-by-step explanation:
The Rutherford atom, also known as Rutherford's planetary model of the atom, was a groundbreaking concept introduced by Ernest Rutherford in 1911. This model proposed that the atom consists of a very small, dense center known as the nucleus which carries a positive charge and contains most of the atom's mass. Surrounding the nucleus are lighter, negatively charged particles called electrons that orbit the nucleus in a manner similar to planets orbiting the sun. This atomic structure shows that the atom is mostly empty space and marked a significant shift from previous models. Additionally, Rutherford identified the proton, a positively charged particle within the nucleus, and suggested the existence of the neutron, which would be discovered later.