history of an atom

8. when two elements combine to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers
9. the atom consists of a nucleus surrounded by orbiting electrons
11. introduced the atomic theory into chemistry and known for his work on human optics
12. one of the greatest philosophers who ever lived and the first genuine scientist in history
13. best known for his pioneering studies of radioactivity and the atom
14. all matter is composed of atoms
15. a central figure in the development of the atomic theory of the universe

1. a theory of the nature of matter
2. based on the combination of four different roots that give rise to life and matter
3. the electrons encircle the nucleus of the atom in specific allowable paths called orbits
4. known for adapting Rutherford's nuclear structure to Max Planck's quantum theory and created the Bohr model
5. discovered the electron and then went on to propose a model for the structure of the atom
6. all samples of a given chemical compound have the same elemental composition by mass
7. represents atoms containing a nucleus of protons and neutrons and a vague gradient or cloud surrounding it containing the electrons
10. the atom is a sphere of positive charge and negatively charged electrons are embedded in it to balance the total positive charge