Across
- 3. the size of a proton or a neutron
- 5. neutral subatomic particles
- 7. Group __ are the most stable elements
- 11. the area outside an atom's nucleus which contains all of the electrons
- 13. cannot be broken down into a simpler substance and have the same chemical properties
- 15. have the same number of valence electrons
- 16. share characteristics of both metals and nonmetals
- 20. the name of the eighteenth group
- 21. the basic unit of a chemical element
- 22. mainly found on the left side of the periodic table
- 24. negative subatomic particles
- 26. the sum of an atom's protons and neutrons
- 29. sodium and magnesium are in the same __
Down
- 1. __ electrons are in the outermost energy shell of an atom
- 2. elements in the same group have similar chemical __
- 4. The second and third electron shells can hold up to __ electrons each
- 6. These subatomic particles determine an atom's degree of reactivity
- 8. a graphic organizer of all the known elements in the universe
- 9. The first electron shell can hold only __ electrons
- 10. used to describe an atom's ability to chemically bond with another atom
- 12. The __ indicates the number of molecules in a chemical formula.
- 14. positive subatomic particles
- 17. The most reactive elements are located in group __.
- 18. mainly found on the right side of the periodic table
- 19. __ have the same number of energy levels or energy shells
- 23. number of protons contained within an atom's nucleus
- 25. These subatomic particles determine an atom's identity.
- 27. The __ indicates the number of atoms for a specific element in a chemical formula.
- 28. oxygen and sulfur are in the same __