Question

Which of the following statement about the modern periodic table is correct?

(a) It has 18 horizontal rows known as periods.
(b) It has 7 vertical columns known as periods.
(c) It has 18 vertical columns known as groups.
(d) It has 7 horizontal rows known as groups.

Answer 1

(c) It has 18 vertical columns known as groups.
In the modern periodic table, there are 18 vertical columns known as groups.