In periodic table isotopes are not given separate places.

Why are f-block elements placed at the bottom of the periodic table ? Give the names of the series present in the block.

In the modern periodic table of the first ten elements which are metals?

In the modern periodic table elements are arranged in order of

In a periodic table the average atomic mass of magnesium is given as 24.312 u. The average value is based on their relative natural abundance on earth. The three isotopes and their masses are "_12^24Mg (23.98504u), "_12^25Mg (24.98584u) and "_12^26Mg (25.98259u). The natural abundance of "_12^24Mg is 78.99% by mass. Calculate the abundances of other two isotopes.

What were the two major shortcomings of meneleev's periodic table? How have these been removed in the modern periodic table?

How could modern periodic table remove various anomallies of mendeleev periodic table/

Modern periodic table has groups : 17 16 18 7

Indicate the atomic number of elements of period 3 of modern periodic table:element forming negative ions.