Science Chemistry

5. positively charged particle in the nucleus of an atom
8. pure substance formed when at least one metal and one non-metal combine
11. substance that cannot be broken down into other substances
14. material that electric charge can move through easily
16. the sum of the number of protons and neutrons in an atom
18. pure substance formed when non-metals combine
19. group 18 elements in the periodic table;the most stable and unreactive elements
21. a group of atoms joined by covalent bonds
22. atom that has become electrically charged because it has lost or gained electrons; a positive ion is an atom that has lost one or more electrons;a negative ion is an atom that has gained one or more electrons
23. neutral particle in the nucleus of an atom
24. description of an object that has equal amounts of positive and negative charges

1. group 17 elements in the periodic table;the most reactive non-metals
2. substance that reacts with another substance or substances in a chemical reaction to create new substances with different properties
3. a table in which the elements are organized by their physical and chemical properties
4. anything that has mass and occupies space
6. combination of pure substances
7. group 2 elements in the periodic table; their reactivity is not as strong as that of the alkali metals
9. reaction that takes place when two or more substances react to form new substances
10. element that has both metallic and non-metallic properties
12. mixture in which the different substances that make up the mixture are visible
13. compounds whosemolecules contain carbon
15. mass of one atom of an element calculated from the total number of protons,neutrons, and electrons of that atom; measured in atomic mass units
17. vertical column of elements in the periodic table
20. mixture of two or more pure substances that looks like one substance