Chapter 5, Problem 3KT

Interpretation Introduction

Interpretation:

The key term corresponding to the definition “a horizontal row of elements in the periodic table” is to be stated.

Concept introduction:

The elements in a modern periodic table are arranged in an increasing order of their atomic number. In the modern periodic table, the horizontal rows are known as periods, whereas vertical columns are known as groups. There are $7$ periods and $18$ groups in a modern periodic table.