Across
- 4. cloud the system of electrons surrounding the nucleus of an atom
- 5. amount of matter in a substance
- 7. positive charge
- 9. developed the Bohr model
- 10. a definite volume but no definite shape
- 11. a tabular array of the chemical elements organized by atomic number, from the element with the lowest atomic number to the highest atomic number
- 13. the number of a chemical element in the periodic system
- 16. mass of a unit volume of a material substance
- 17. mass of an atom
- 18. made the periodic table
Down
- 1. the smallest particle of a substance that has all of the physical and chemical properties of that substance
- 2. negative charge
- 3. composed of or resulting from union of separate elements
- 6. a definite shape, as well as mass and volume
- 8. neutral charge
- 12. a pure substance consisting only of atoms that all have the same numbers of protons in their nuclei
- 14. the central part of an atom that comprises nearly all of the atomic mass and that consists of protons and neutrons
- 15. no definite volume and no definite shape
- 17. made up of protons, neutrons and electrons