Question

What is the Mendeleev's periodic Law? how many periods and groups there in Mendeleev's periodic table?

Answer 1

If the elements are arranged in order of increasing at masses then those with similar properties are repeated at regular intervals. There are 7 periods and 18 groups

Answer 2

Mendeleev's periodic Table

♦ Mendeleev's periodic table contains vertical columns called 'groups' and horizontal rows call 'periods'.

♦ There are in all eight groups, i.e., group I to group VIII. Each of these groups from I to VII is divided into two sub-groups : A and B. Group VIII has no sub group. Inert gases were not known at that time.

♦ All elements of a sub-group ( or of the group VIII, which has no sub-group) have similar properties and show the same valency, which is equal to the group number ( for upto Group IV ) or group number subtracted from eight ( for Groups V-VII ).

♦ In a period, elements gradually change from metallic to a non-metallic character or metallic character decreases as one moves from left to right across the horizontal row.

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