Across
- 2. particles with a positive 1 charge
- 4. the weighted-average mass of the mixture of its isotopes
- 5. the horizontal rows in the periodic table
- 8. the sum of the protons and the neutrons in the element
- 11. particles with a negative 1 charge
- 12. atoms of the same element that have different numbers of neutrons. (different mass numbers)
- 13. the smallest piece of matter that still retains the properties of the element
- 14. protons and neutrons are made of even smaller particles called
- 15. neutral particles that have 0 charge
Down
- 1. the number of protons in the element
- 3. the elements are arranged by increasing atomic number and by changes in physical and chemical properties
- 6. cloud area around the nucleus of an atom where its electrons are most likely found
- 7. the vertical columns in the periodic table
- 9. uses the symbol of the element and dots to represent the electrons in the outer energy level
- 10. small positively charged center of the atom. contains the protons and neutrons