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Thursday, October 27, 2011

THE MODERN PERIODIC TABLE 10th chemistry

THE MODERN PERIODIC TABLE 10th chemistry
The modern version of the periodic law is stated as :
“The physical and chemical properties of the elements are the periodic functions of their atomic masses”.
LONG FORM OF THE PERIODIC TABLE
There are many forms of the periodic tale. The long form of the periodic table is the most convenient and the most widely used and is presented here. The horizontal rows are called PERIODS. Elements having similar chemical and physical properties appear in vertical columns and are known as GROUPS or FAMILIES. Altogether there are seven periods and 18 groups.
PERIODS
1ST Period Contain only 2 elements namely 1H, 2He and is the shortest period.
IInd Period Contains 8 elements namely 3Li, 4Be, 5B, 6C, 7N, 8O, 9F and 10Ne is known as the short period.
IIIrd Period Contains 8 elements : 11Na, 12Mg, 13Al, 14Si, 15S, 16S, 17Cl, and 18Ar. The IIIrd period is also known as short period.
IV Period starts with potassium and contains 18 elements : 19K, 20Ca, 21Sc, 22Ti, 23V, 24Cr,
25Mn, 26Fe, 27Co, 28Ni, 29Cu, 30Zn, 31Ga, 32Ge, 33As, 34Se, 35Br and 36Kr and is known
as long period.
V Period Starts with rubidium and contains 18 elements : 37Rb, 38Sr, 39Y, 40Zr, 41Nb, 42Mo, 43Tc,
44Ru, 45Rh, 46PD, 47Ag, 48CD 49In, 50Sn, 51Sb, 52Te, 53I, 54Xe.The fifth
VI Period Consists of 32 elements, starting from cesium (55Sc) and ending with radon. It is
called as longest period. This period includes the 4f shell that includes Lanthanides
(58Ce, …..71Lu).
VII Period Like the sixth period would have a theoretical maximum of 32 elements. This period
however is incomplete and at present contains 19 elements starting from 87Fr
(francium) to 92U. All these elements are naturally occurring but rest are radioactive with very short half lives. These also include a part of inner transition elements, 90Th, …. 103Lr.
GROUPS
The atom of the element in a single vertical column have the same or very similar electronic configurations in the highest occupied orbitals and are therefore said to belong to the same
GROUP or FAMILY of elements. According to the new IUPAC recommendations the groups are numbered form 1 to 18. Bases on the electronic configuration, we can classify elements in to four types.
1. Noble Gases
2. Representative Elements
3. Transition Elements and
4. Inner Transition Elements
1. Noble Gases

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