Match the scientists with their contributions to atomic theory by writing the correct letter on the appropriate blank line. Use each letter once.

A. Aristotle
B. Niels Bohr
C. James Chadwick
D. John Dalton
E. Louis de Broglie
F. Democritus
G. Werner Heisenberg
H. Dmitri Mendeleev
I. Hantaro Nagaoka
J. Ernest Rutherford K. Erwin Schrödinger
L. J. J. Thomson

1. He was the codeveloper of the electron cloud model of the atom.

2. He discovered the existence of the neutron in the atomic nucleus.

3. He discovered the existence of the electron and developed the plum
pudding model.

4. He proposed that electrons have wavelike properties.

5. His opinion about the atom carried weight for 2000 years.

6. He believed that matter was made of small indivisible particles,

7. He discovered that atoms had a dense, positively charged nucleus.

8. He proposed that electrons move in fixed orbits around the nucleus of an atom.

9. He suggested that an atom has a central nucleus with electrons orbiting around the nucleus.

10. He developed mathematical equations leading to the electron cloud model of the atom.

11. He was the first to publish a periodic table of the elements.

12. He developed the basis for our modern understanding of atomic theory.