Question

In modem periodic Table the number of columns and periods are respectively _ and _

​

Answer 1

Answer:

In the mordern periodic table the number of columns and periods are respectively

18 and 7.

Explanation:

COLUMNS (GROUPS) IN MORDERN PERIODIC TABLE CONSIST ELEMENTS HAVING SAME VALENCE ELECTRONS i, . e SAME VALENCY. WHEREAS, IN THE PERIODS, ELEMENTS ARE ARRANGED IN THEIR INCREASING ATOMIC NUMBER AND THE VALENCE ELECTRONS INCREASES BY ONE ON MOVING FROM LEFT TO RIGHT.

Answer 2

In modern periodic table the number of groups/columns and periods/rows are respectively 18 and 7