Question

How many periods are present in the modern periodic table
and why the 1 and 2 periods are known by the name very
short and short periods?​

Answer 1

Answer:

7

Explanation:

they are horizontal columns

Answer 2

Answer:

7 periods with horizontal rows..

1-s block s1 alkali metals

2-s block s2 alkaline Earth metal ....plz mark as brainliest