Across
- 6. Gases – Group 18 elements that are inert under normal conditions.
- 8. – Radioactive elements from atomic numbers 89–103.
- 10. – A division of principal energy levels in an atom.
- 11. Affinity – The energy changes when an atom gains an electron.
- 12. – Positively charged particle in an atom.
- 13. – The electrons in the outermost shell of an atom.
- 15. – Neutral particle in an atom's nucleus.
- 16. – The smallest unit of matter.
- 18. – A vertical column in the periodic table.
- 20. – Rare earth metals from atomic numbers 57–71.
- 21. – A region with a high probability of finding an electron.
- 23. – Nonmetals in Group 17 are known for forming salts.
Down
- 1. Radius – Distance from the nucleus to the outermost electron shell.
- 2. – Atoms with the same number of protons but different neutrons.
- 3. Metals – Highly reactive metals in Group 1 of the periodic table.
- 4. – A measure of an atom's ability to attract electrons.
- 5. Energy – The energy required to remove an electron from an atom.
- 7. – Negatively charged particle in an atom.
- 9. – A phenomenon that reduces the effective nuclear charge felt by outer electrons.
- 12. – A horizontal row in the periodic table.
- 14. – Central part of an atom containing protons and neutrons.
- 17. Metals – Elements in the d-block of the periodic table.
- 19. – Atom or molecule with a net electric charge.
- 22. – The capacity to do work or cause change.