Matter Review

2. discovered electrons
3. a substance that consists of two ore more different elements chemically bonded together
5. a characteristic of matter that you can observe or measure without changing the identity of the matter
7. mixture/ a type of mixture that is unevenly mixed
10. describes elements that spontaneously emit radiation
11. credited with discovering neutrons and that they are neutral
14. states that electrons can be found in the electron cloud
15. an atom that is no longer neutral because it has gained or lost electrons
16. the process that occurs when an unstable atomic nucleus changes into another more stable nucleus by emitting radiation
18. the ability of one substance to dissolve in another
20. atomic mass/ the average mass of an element's isotopes, weighted according to the abundance of each isotope
23. the smallest piece of an element that still represents the element
24. a type of mixture that is evenly mixed
25. the number of protons in an atom
27. Said, "Atoms are small solid objects that cannot be divided, created, or destroyed"
28. anything that has mass and takes up space

1. the sum of protons and neutrons
4. to form a solution by mixing evenly
6. a characteristic of matter that can be observed as it changes to a different type of matter
8. matter with a composition that is always the same
9. an atomic particle with a positive charge
12. a change in matter in which the substances that make up the matter change into other substances with new physical and chemical properties
13. any of two or more atoms of the same element that have different numbers of neutrons
17. discovered the nucleus
19. the mass per unit volume of a substance
21. states that electrons orbit the nucleus
22. a neutral particle found in the nucleus of an atom
26. an atomic particle with a negative charge