Question

No of element in seventh period of mendeleev periodic table

Answer 1

Answer:

six elements it contains two sub groups

a b

a contains 4 elements and b contains 2 elements

Answer 2

Question:-

No of element in seventh period of mendeleev periodic table?

Answer:-

Six elements ✓

It contains two sub-groups : A and B. Group A contains 4 elements and group B contains 2 elements.

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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