Across
- 2. a substance that cannot be separated or broke down
- 6. the smallest unit of an element that maintains the pro
- 7. number the number of protons in the nucleus of an atom
- 8. in chemistry, a column in the periodic table
Down
- 1. is a horizontal row of the periodic table
- 3. in nuclear physics, the sum of the numbers
- 4. a subatomic particle that has no charge
- 5. a subatomic particle that has a negative charge
- 9. a subatomic particle that has a positive charge