Question

how many groups and periods in modern periodic table ​

Answer 1

There are 18 groups and 7 periods in the modern periodic table. (a) The atomic size and metallic character of elements increase down a group. (b) The atomic size and metallic character of elements decrease from left to right in a period. the number of periods is 7 and the number of groups is 18.

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Answer 2

Explanation:

there are 18 groups and 7 periods in the modern periodic table