1. Periodic table of elements

2. Alkali Metals  Lithium  Sodium  Potassium  Rubidium  Cesium  Francium Alkali metals are among the most reactive metals All of the alkali metals are found naturally in nature They also have low boiling and melting points and are less dense than most elements

3. Alkali Earth metals  Beryllium  Magnesium  Calcium  Strontium  Barium  Radium Two electrons in the outer shell Low electron affinities Low electronegativity's

4. Noble Gases  Helium Helium  Neon Neon  Argon Argon  Krypton Krypton  Xenon Xenon  Radon Radon The noble gases are used in industry in arc welding They are extremely rare in nature These gases were not discovered until the last five years of the 1800s

5. Non-metals  Hydrogen Hydrogen  Carbon Carbon  Nitrogen Nitrogen  Oxygen Oxygen  Phosphorus Phosphorus  Sulfur Sulfur  Selenium Selenium substance that does not have such characteristic properties of metals The atoms of nonmetals generally are small and contain relatively large numbers of electrons These elements have few physical properties in common

6. Halogens  Fluorine  Chlorine  Bromine  Iodine  Astatine Halogens form diatomic molecules in their elemental states Chlorine was the first halogen to be discovered in 1774 Halogens are used in everyday life there our water are toothpaste lots of things

7. Rare Earth Elements  Terbium  Dysprosium  Holmium  Protactinium  Uranium  Neptunium Scandium is found in most rare earth element Rare earths are used as catalysts, phosphors, and polishing compounds Lanthanum is used for such as night vision goggles

8. Metalloids  Boron Boron  Silicon Silicon  Germanium Germanium  Arsenic Arsenic  Antimony Antimony  Tellurium Tellurium  Polonium Polonium Ionization energies between those of metals and nonmetals Possess some characteristics of metals/some of nonmetals Reactivity depends on properties of other elements in reaction

9. Transition Metals  Scandium  Titanium  Vanadium  Chromium  Manganese  Iron  Cobalt The transition metals are the metallic elements that serve as a bridge, or transition, between the two sides of the table. Not all d block elements count as transition metals These elements are very hard, with high melting points and boiling points

10. Other Metals  Aluminum  Gallium  Indium  Tin  Thallium  Lead  Bismuth They are solid metal under standard conditions. Like most metals they are malleable, ductile, and good conductions of heat and electricity. They have a fairly high density. In comparison to transition metals, they generally are softer and have lower melting and boiling points.

11. The Periodic table of elements