Across
- 4. The average mass of all the isotopes of that element.
- 5. How many elements were on the periodic table in 1869?
- 6. Particle in the nucleus of atoms.
- 9. A chart showing all the elements arranged according to the repeating pattern of their properties?
- 10. The dense center of an atom.
Down
- 1. Atoms with the same number of protons and different numbers of neutrons.
- 2. The sum of all the protons and neutrons in the atom.
- 3. Who discovered a set of patters that apply to all the elements?
- 7. How many liquids were known in 1869?
- 8. A positively charged particle in an atoms nucleus.