The+Major+divisions+of+the+periodic+table+&+Metals+Non-metals+and+semi+conductors

Key Terms: **
 * The Major divisions of the periodic table & Metals Non-metals and Semiconductors **.[[image:http://www.bbc.co.uk/schools/gcsebitesize/science/images/38_modern_periodic_table.jpg align="right"]]** Part 1 ****
 * 1) **Period**: all the elements going **from left to right** in each row.
 * 2) **Group/Family**: all the elements going **from top to bottom** in each colomn.

** Special groups, periods and blocks in the periodic table: **


 * Representative Elements:** the main groups of elements except the central blocks. (The blue, grey, green and red columns in the figure.)


 * Alkali Metals:** located in the ** first ** group on the ** left ** . (The blue column in the figure.)


 * Alkali Earth Metals:** located in the **second** group on the ** left **. (The left grey column in the figure.)


 * Transitional Metals:** located **between** representative elements. (The yellow columns in the figure.)


 * Halogens:** located in the ** second ** group on the ** right **. (The green column on the right.)


 * Noble Gases:** located in the ** first ** group on the ** right **. (The red column on the right.)


 * Lanthanides:** located in the ** first ** period on the** bottom **. (Not shown in the figure.)


 * Actinides:** located in the ** second ** period on the** bottom **. (Not shown in the figure.)

** Part 2 ** ** 2.What properties do nonmetals have? **
 * 1.What properties do metals have? **
 * reflecting light
 * not crystal
 * conduct electricity and heat well
 * easy to bend when in thin sheets
 * able to being shaped or drew out
 * solid at room temperature
 * gas, liquid or brittle solid at room temperature
 * conduct electricity and heat poorly
 * not reflecting light in surface when solid
 * not crystal to half crystal when solid
 * divided into two subgroups based on electrical conductivities


 * 3.What are semiconductors ** **?**
 * Actually, they are a kind of nonmetals with **electrical conductivities** t hat increase by tempratures.
 * They include the elements of B, Si, Ge, As, Se, Sb, Te.


 * 4.What are the two trends that exist among the elements in the periodic table? **
 * The properties of elements become more metallic ** going left a period .**
 * The properties of elements become more metallic ** going down a group or family **.

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