Question

can someone help me stick this question out of my brain cause I know the answer but can put ideas together ..:( I know , complicated ...how scientific observations led to the development of, and changes to, the periodic table

Answer 1

see, according to earlier theory elements were arranged according to their properties that is mendelev's periodic table but later after developing new theories elements were placed according to their atomic number and weight....(size)...also as soon as newer elements were developed newer arrangements were made....like after knowing the properties of transition metals lanthanide and actinoids were developed....

Answer 2

I see ,, thank you again ! :)

Answer 3

anytime