Periodic Table

3. the number of protons in an atom's nucleus
9. group 18, generally very stable, colorless, and odorless
10. physical properties and appearances like metals, chemical properties like non-metals
13. able to be stretched into a thin wire
14. table of the chemical elements arranged in order of atomic number
15. average quantity of matter that an atom of that element contains
17. groups 3 through 12 and the lanthanides and actinides
18. vertical column of elements in the periodic table
19. the tendency of a substance to undergo chemical reaction by losing or gaining electron(s)
20. conduct heat and electricity, are shiny, and can be hammered into sheets or drawn into a wire
21. notation of one or two letters that represents a chemical element
22. 'fixer' of the periodic table, organised it by atomic number

1. group 17 of the periodic table
2. horizontal row of the periodic table
3. the second group of the periodic table
4. able to be shaped or flattened into a thin sheet
5. another word for group
6. substance composed of atoms with different atomic numbers
7. first group of the periodic table
8. maker of the periodic table, but organised it by mass
11. the principle that the properties or characteristics of the elements recur periodically as their atomic numbers increase
12. substance composed of atoms with the same atomic number
16. determines the number of valence electrons
21. material that conducts heat or electricity
23. chemicals that do not conduct heat and electricity, are not shiny, and cannot be hammered into sheets or drawn into a wire