What was wrong with early periodic tables?

Question

I have a Chemistry project and one of the easier question I thought would be this, but I can't find it on the internet anywhere in an understandable form.

Thanks

Answer 1

Several possible problems:
a. The periodic tables were incomplete since not all the elements were not known. For instance, hafnium was not known to be a separate element from zirconium for some time.
b. The electronic arrangement into orbitals, suborbitals, and +/- portions of suborbitals was not known, so the location of transition and rare-earth metals may be out of whack
c. Some element symbols were changed over the years.
d. If the table is not in English, some of the symbols may differ. For instance, niobium was known as columbium to metallurgists, and iodine was call "Jod" in German.

Answer 2

Early Periodic Table

Answer 3

The early periodic table were not ordered in any way until an English chemist named John Newlands arranged the atoms by atomic mass. However, Russian chemistry professor Dmitri Ivanovich Mendeleev and German Julius Lothar Meyer are credited with its arrangement because they corrected some of Newland’s mistakes and plotted undiscovered elements using the table.

Answer 4

Nothing was wrong with earlier periodic tables, they were just grouped differently. As time went on we learn and understand more and the arrangement of the table is now easier to understand and grouped in terms of atomic mass and electron arrangement.

you really need to look at a text bnook rather than the internet.

If you must use the net, then try to stick to University websites rather than your top yahoo search results as these will be sites written by scientists with qualifications in the field rather than just a web designer.

Good luck

Answer 5

The early periodic tables left room for undiscovered elements. You could work on the manmade elements or the later discovered ones.
The earliest ones went by mass instead of atomic number.
This would be a good project as you can see which elements were incorrect by mass. check argon and calcium, there are a couple others.

Answer 6

Oooooooo i had to do this for my GCSE exams a couple of months agoo. I can only remember snippets though..
but there were two people one called something like meendelev? or something and one grouped them by reactivity and another person by atomic mass? Try looking that mans name up and it should tell you something about his mistakes.
hope it helps even though it's a pretty weak answer!

Answer 7

well early periodic table was made on the base of atomic mass, so tht we had not the elements of continuous atomic mass no ,,, so could not able to predict the adsence of specific element.

Answer 8

Yeah, wiki up the names in dudas's reply and you are golden.

Answer 9

they were based on properties of materials and appearance rather than atomic weight