Q1.Write down advantages and disadvantages of Mendeleev's Periodic table? Plz Help Me I Want To Make Notes For It

the advantage is that he discover many element unknown that time

And the disadvantage is wrong order of atomic masses and the position of isotopes

Explanation:

Disadvantage: the isotopes and no separate position also as they have different atomic mass but same atomic number. Since the change in atomic mass of two successive elements was not constant therefore it was difficult to predict the number of missing elements with the help of atomic number only.

It could predict the existence of other elements and could predict their properties so, as to leave space in the periodic table. It could accommodate all the sixty elements discovered at that time and could accommodate the noble gases which, where discovered later.

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year