Question

Explain the following terms:-
Magic number, alkali, alkaline, alkaline earth metal, Chalcogen, halogen, modern periodic law, valency, electronic configuration, isotops, triads, and law of octave​

Answer 1

valency

the valency of an element may also be defined as the number of electrons donated accepted or shared by the atom of that element so as to compete an octet of electron or duplet in case of hydrogen.

electronic configuration

the arrangement of electrons in different shells of the atoms of an element is called the electronic configuration of the element

isotopes

atoms of the same element having different mass numbers are called isotopes