Question

how many periods were present in mandeleev's Periodic table?​

Answer 1

Answer:

7 periods in mandeleevs periodic table

Answer 2

Answer:

Seven

In Mendeleev periodic table, vertical columns in the periodic table and horizontal row in the periodic table were named as groups and period respectively. The periodic table is composed of seven horizontal rows or periods and is numbered between 1 and 7.

Explanation:

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