Across
- 3. average mass of diff forms of the same element
- 5. what an element is identified as
- 6. regions around the nucleus
- 7. horizontal
- 9. vertical; families
Down
- 1. increases as you read left to right
- 2. located in the farthest level
- 4. the gas family; mostly non-reactive
- 8. a unique (set of) letter(s)