Elements, Molecules, and Compounds

2. the shells where electrons orbit the nucleus
6. electrons located in the outermost energy level of an atom
8. the center of an atom which contains neutrons and protons
11. the negatively charged particle in an atom
12. molecule that contains carbon-hydrogen bonds
15. a charged atom or molecule
17. the positively charged particle in an atom
20. a visual representation of the elements and the bonds between them
21. a molecule that emits radiation
22. two or more elements
23. equals the sum of protons and neutrons
25. mass can change from one form to another but the total amount of mass remains constant

1. type of bond formed when electrons are shared
3. a diagram that indicates the number of valence electrons in an atom
4. a pure substance that cannot be reduced into a simpler substance
5. the particle in an atom having no charge
7. a chart that displays elements and is organized by the number of protons (horizontally) and valence electrons (vertically)
9. type of molecule that has a ring structure
10. element symbols and numbers that indicate the 'recipe' to create a molecule
13. variations of the same element
14. substances made up of carbon and hydrogen atoms
16. represents the number of protons in an atom
18. type of bond formed when electrons are transferred
19. the basic unit of matter
24. two or more atoms