Across
- 1. Gas Stable, non-reactive element in Group 18.
- 4. Atomic number of phosphorus.
- 5. the smallest unit of matter that makes up elements.
- 6. 2 Ion with two positive charges.
- 7. Electrons in the outermost shell.
- 8. number number of protons in an atom.
Down
- 2. Negative particle orbiting the nucleus.
- 3. Vertical columns on the periodic table.
- 6. Horizontal rows on the periodic table.
- 9. Two or more elements chemically combined.