Question

mention the number of elements in the 1st 3rd 5th and 6th period​

Answer 1

first period contain two elements only. second and third periods contain eight elements. fourth and fifth periods contain eighteen elements only. sixth period consists of 32 elements.

Answer 2

The number of  elements in the 1st 3rd 5th and 6th period​s is:

• For the first period, there are two elements and are Hydrogen(H) and Helium(He).

• For the second period, there are eight elements and some of them are Lithium(Li), Carbon(C), Oxygen(O), Neon(Ne).

• For the third period, there are eight elements and some of them are Sodium(Na), Aluminum(Al), Chlorine(Cl), Argon(Ar).

• For the fourth period, there are eighteen elements and some of them are Potassium(K), Copper(Cu), Iron(Fe), Germanium(Ge).

• For the fifth period, there are eighteen elements and some of them are Rubidium(Rb), Silver(Ag), Tin(Sn), Xenon(Xe).

• For the sixth period, there are 32 elements and some of them are Barium(Ba), Mercury(Hg), Bismuth(Bi), Radon(Rn).