I = Number of Electrons in outer shell.

Property	Metals	Nonmetals	Metalloids
Luster	Shiny	Not shiny	Not shiny
Hardness	Hard	Brittle	Brittle
Malleable and ductile	Yes	No	No
Conduct heat and electricity	Yes	No	Simiconductors
State	Solids (and one liquid)	Varies	Solid

Group 18 - Noble Gases: Noble gases are almost entirel unreactive. This lac of reactivity stems from the fact that completely filled s- and p-orgitals (see Chapter 5) makes them very stabel.  As a result, very few noble gas compounds can be made.  Noble gases are used in advertising signs, toy ballloons and blimps, and as inter atmospheres in locations where reactions woiuld be undesirable.
(Because of the high stability of thenoble gas electron configurations, other elements gain or loose electrons to obtain the electron configuration of the closest noble gas.  This tendency to become like the closet noble gas is referred to as the "octet rule" because most noble gases contain a total of eight s- and p- electrons in their outer shell (helium has only tow elctrons, as there are not p-orgitals in the first energy lever.) [Chemistry, Ian Gunch 78]

Group 1 (except for hydrogen)- Alkali metals are highly reactive, combining readily with air and water.  Though they are metallic, their densities are losw (only rubidium and cesium are denser than water) and they are soft enough to be cut with a knofe.  The high reactivity of the alkali metals comse from the fact that they have only one more eclecton than the very stable noble gases.  As a result, they react vigouously in attempts to lose this extrar elctron.  Alkali metals can be found in sodium vapor fog lamps and in the psychiatric drug lithium carbonate.

Group 2 - Alkaline earth metals: The alkaline earth metals have many of the same properties as the alkali metals, although they are less extreme.  For example, most alkaline earth metals react with air and water, but much less violently than the alkali metals.  Alkaline earth metals are generally harder than the alali metals, but are still softer than many other metals.  The diminished reactivity of the alkaline earth metals can also be explained by their electron configuratrtions.  Because thy have to loose tow electrons to be come like a noble gas. thay rea somwhat less reactive than the alkali metals.

Group 3-12 -d-Transition Metals (often called simply 'transitions metals'): Through propertires of the d-transition elements vary greatly, many of them are hard, have high melting and boiling points, are excellent conductors of heat and electrictity, and have moderate to low reactivities.  Transition metals are used for a variety of purposes such as structual materials in buildings, power transmission lines, jewelry, and knives.

f-Transition Metals (somtimes called "inner transition metals"): The f transition elements consist of the two rows a the bottom of the periodic table, and aren't properly said to be in any of the 18 "groups".
 
The top two, also known as the lanthanides, consists of shiny reactive metals. Becuse many lanthides emit colored light when hit by a beam of elcetrons, they are used as phosphors in telvision sets and flouirescent light bulbs.

The bottom row, also known as actinides, are primarily radioactive elements, that have a wide variety of uses such as nuclear fuel sources, smoke detectors, and atomic bombs.

Group 17- Halogens: These are highly reactive elements that combine readily with metals to form salts.  This extremely high reativity comes from their electron configurations - because they need olny one more electron to have the electron configurations ofa  noble gas, they react vigorously to pick up that electron whenever possible.  the halogens are ditomic elements, meaning that they have tghe general formula X₂  (for example, floourine exists as F₂   in its pure form).  Flouirine and chlorine are gases under standared conditions, while bromine is a liquid and iodine is asolid.  Halogens are widely used in water treatment, in the manufacture of other chemicals, and in plastics such as Teflon.

Hydrogen- The weirdo: Hydrogen has properties unlike any other element in the periodic table.  Though it's found in the metallic region of the period table, it is a nonmetallic gas.  It is diatomic, found as H₂ .  Hydrogen reacts slowly with other elements at room temperature but may react blindingly fast when heated or catalyzed.  Hydrogen is used in the manufacture of ammonia, sulfuric acid, and methanol, and is widely discussed as a alternative to oil as a fuel.

Element	Electron Configuration	Ionisation Energy in kJ/mol	Atomic radious
H	1s1	1311.3	79
He	1s2	2361.3	0.0
Li	1s22s1   , [He]2s1
Be	1s22s2