Sunday, October 3, 2010

Groups, Families, Periods and Valence of the Periodic Table

What are Groups? 
  • A group is a vertical column in the Periodic Table of Elements. They are considered the most important method in classifying the different elements. 
  • Groups are the elements having the same outer electron arrangement. The outer electrons are also called the valence electrons.
  • Since they have the same number of valence electrons, the elements in a group shares the same chemical properties.
  • The Roman numerals listed ABOVE each group are the usual number of valence electrons. 
  • These are the groups: IA, IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA

What are Families?
  • Groups are also known as Families. The families are the names representing each group. 
  • There are 9 different families, and these are the:
  • Alkali Metals
  • Alkaline Earth Metals
  • Transition Metals
  • Boron 
  • Carbon
  • Nitrogen
  • Chalcogens
  • Halogens
  • Noble Gases

What are Periods? 
  • Periods are the horizontal rows of elements found in the Periodic Table of Elements. There are 7 periods in the Periodic Table.
  • The periods represents the energy level of an atom.
  • The number of elements in a period increases as you move down because there are more sub levels per level as the energy level of the atom increases.
  • According to the table below, not all the periods have the same number of elements.    

Period Number
Number of Elements

What are Valence?
  • Valence is also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element.
  • Valence is the number of electrons needed to fill the outermost shell of an atom. 
  • For example, when you go across the table from carbon to nitrogen to oxygen, the number of valence electrons increases from 4 to 5 to 6. As we go from fluorine to neon to sodium, the number of valence electrons increases from 7 to 8 and then drops down to 1 when we start the new period.
How to get the element using the periods and groups!
  • You can find an element even without the given atomic number just by using the groups and periods. Example: Look for the element that is located on Period 2, Group 4. The element is Carbon because its on the row of period 2 and it is under Group 4.
Try this! Find the element given the period and group number only.
  • Period 4, Group 6
  • Period 2, Group 2
  • Period 5, under the Alkali Metals
  • Halogens family, along period 5. 
Made by: Group 3
Marj Mendoza
Roxy Trillanes
Isabella Meily
Eula Manibog
Djoseth Macomb