Consider the statements below and identify the correct answer.
Statement-I: Modern periodic table has 18 vertical columns known as groups.
Statement-II: Modern periodic table has 7 horizontal rows known as periods.

Correct option is A

The correct answers is option (A).

Statement-I: Modern periodic table has 18 vertical columns known as groups.
Correct: The modern periodic table consists of 18 vertical columns, which are referred to as groups.

These groups represent elements that have similar chemical properties due to having the same number of valence electrons. For example, Group 1 contains alkali metals, and Group 17 contains halogens.

Statement-II: Modern periodic table has 7 horizontal rows known as periods.
Correct: The modern periodic table has 7 horizontal rows, which are called periods. Each period corresponds to the filling of a new electron shell. As you move across a period from left to right, the atomic number increases, and the properties of elements change in a predictable manner.