EVERYDAY SCIENCE

Detailed explanation-1: -In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom.

Detailed explanation-2: -(i) The elements in the Modern periodic table are arranged on the basis of their decreasing atomic number. (iii) Isotopes are placed in an adjoining group(s) in the periodic table. In Mendeleev’s periodic table, elements are arranged in an increasing order of their atomic number.

Detailed explanation-3: -The number of electrons in an element is fixed. No two elements can have the same atomic number. Hence, elements can be easily classified in the increasing order of their atomic numbers.

Detailed explanation-4: -Answer and Explanation: The periodic table is arranged by atomic number, as the atomic number is an element’s most fundamental designations. The atomic number provides an element’s number of protons and ergo its respective number of electrons.