Across
- 3. Russian scientist who organized the first periodic table (by atomic mass)
- 4. organized the elements by atomic number(number of protons)
- 7. number of elements on the table
- 8. also known as families (18 of them)
- 9. number of periods on the table
Down
- 1. (partially)indicated by group number
- 2. studied chemical bonding
- 5. found the orbital
- 6. elements in the same group have __ properties