The present concept of the structure of an atom is given by which scientist?

The correct answer is option 'c) Niels Bohr'.

Explanation:

Niels Bohr was a Danish physicist who made significant contributions to the understanding of atomic structure and quantum theory. He is best known for his atomic model, also known as the Bohr model, which provided a new understanding of how electrons occupy energy levels around the nucleus of an atom.

Key Points:

- Rutherford: While Rutherford made important contributions to the understanding of atomic structure, his model did not provide a complete explanation of the behavior of electrons within an atom. Rutherford's model described the atom as having a small, dense, positively charged nucleus at the center, with electrons orbiting around it. However, his model could not explain why the electrons did not quickly spiral into the nucleus due to electromagnetic attraction.

- Goldstein: Goldstein, a German physicist, discovered the existence of positively charged particles called protons in 1886. However, his work did not provide a comprehensive model of the atom's structure.

- J.J. Thomson: Thomson, a British physicist, is known for his discovery of the electron in 1897. He proposed the "plum pudding" model of the atom, which suggested that electrons were evenly distributed within a positively charged sphere. However, this model was later disproven by Rutherford's experiments.

- Niels Bohr: In 1913, Bohr proposed his atomic model, which built upon Rutherford's previous work. He suggested that electrons occupy specific energy levels or orbits around the nucleus, and that they can jump between these energy levels by absorbing or emitting energy in discrete amounts. This model successfully explained the stability of atoms and the line spectra observed in various elements.

Conclusion:

In conclusion, the present concept of the structure of an atom is given by Niels Bohr. His atomic model, which introduced the idea of discrete energy levels for electrons, revolutionized our understanding of atomic structure and laid the foundation for further developments in quantum mechanics.