Question

Mendeleev periodic table​

Answer 1

Explanation:

see above attachment ...

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.

________________________________