CBSE - X - Chemistry - Periodic Classification of Elements
How could we determine an element on the basis of given group and/or period ?
As per the modern periodic law the elements are arranged in increasing order of atomic number, and there are 18 groups and 7periods. There are 2 elements in 1 period, 8 each in 2 and 3 period, 18 each in 4 and 5 period 32 in 6 period and 7 period is in complete. Also rememember 1 group is called alkali metals, 2 is alkaline earth metals, 3 to 12 are called transition metals and 13 boron family,m 14 carbon family, 15 nitrogen family, 16 oxygen family, 17 halogens and 18 inert gas or nobel gases. Left side and bottom row elements are metals. Right hand side elements and top rows are nonmetals. If the position in period and group is known the atomic number and element can be identifyied as metal or nonmetal.
For example element is present in 14 group and 2period. Count from left, 1 period has 2 elements--H and He, 3 period has 8 elements. Atomic number 3,4, 5, will be in 1, 2 and 13 groups. Atomic number of this element is 6 and it is carbon. the whole group is called carbon family.
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