Tuesday, May 25, 2010

Groups of Periodic table

Representative elements: (1) Alkali metals - (2) Alkaline earth metals
Locate at the left hand side
Elements in the s and p blocks except group 8A
Have completely filled energy levels except the highest level (incompletely)
Form ionic or covalent bonds to achieve the noble gases
Noble gases: elements in group 8A (Group 0)
Their electron configuration is np6 except He (1s2)
Very stable due to having the maximum number of valence electrons their outer shell can hold (may forms compounds but with great difficultly)
Rarely react with other elements since they are already stable
Main transition elements:
Located in the central region of the periodic table between the s-block and p-block main-group elements
Contains 10 groups
Ended with {ns2, (n -1)d1→10
They can divided into 3 series
Inner transition element:
Contains 14 groups
Ended with {ns2, (n -1)d1 → 10, (n-2)f1 → 14}
(1) Lanthanides
Placed in the 6th period
Consists of 14 elements from Cerium Ce58 to Lutetium Lu71
Their outer sub level begin filled 4f
Called rare earth elements because they are difficult to be separated from their compounds
(2) Actinides
Placed in the 7th period
Consists of 14 elements from Thorium Th90 to Lawrencium Lr103
Their outer sub level begin filled 5f
Called radioactive elements because their nuclei are unstable


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