What key discoveries shaped our current atomic model?

Key discoveries that shaped our current atomic model include Dalton's atomic theory, Thomson's discovery of the electron, Rutherford's nuclear model, Bohr's energy levels, and Schrödinger's quantum mechanical model.

John Dalton, an English chemist, proposed the atomic theory in the early 19th century. This theory stated that all matter is composed of tiny, indivisible particles called atoms. Dalton's atomic theory was the first to provide a simple and rational explanation of the nature of matter. However, it was a simplistic model and did not account for the internal structure of the atom.

In 1897, J.J. Thomson discovered the electron, a negatively charged particle present in all atoms. This led to the development of the 'plum pudding' model, where the atom was thought to be a sphere of positive charge with electrons embedded within it. This model was a significant advancement as it introduced the concept of subatomic particles.

Ernest Rutherford, a New Zealand-born physicist, proposed the nuclear model of the atom in 1911. He suggested that the atom consists of a tiny, dense, positively charged nucleus surrounded by a cloud of negatively charged electrons. This model was based on his gold foil experiment, which showed that most of the atom is empty space.

In 1913, Niels Bohr, a Danish physicist, proposed a model where electrons orbit the nucleus in specific energy levels. This model explained why atoms emit light in discrete wavelengths. However, it could not accurately predict the behaviour of larger atoms.

Finally, the quantum mechanical model, developed by Erwin Schrödinger in the 1920s, is the current accepted model. It describes electrons as existing in a cloud-like region around the nucleus known as an electron cloud. This model uses complex mathematical equations to predict the probability of finding an electron in a certain location around the nucleus. It provides a more accurate and comprehensive description of the behaviour of electrons in atoms.