Just a second...4

The ans is given as 4

I want reason

Crystal Field Splitting Energy increases down the group..so down the group the complex becomes more stable.

Try the EAN Rule....

Thanks Govind

@Abhirup : How by EAN rule ????

Since both Pd and Pt belong to same group..so comparing EAN will be of no use..

If they belong to diff groups then how do v compare??

Govind plzz ans this qs i never knew that method I would like 2 know it

The 18 electron rule (also known as the Effective Atomic Number Rule or EAN rule) was originally proposed by N.V. Sigwick when extending the octet rule proposed by G.N. Lewis in applying it to organometallic compounds. The idea behind both of these rules is that in a compound the sum total of all of the electrons would have the configuration of a noble gas.

Formula for calculating EAN = atomic number of metal - charge on the metal(here the charge is taken with sign) + number of ligands around metal * 2

the complexes satisfying the EAN rule are said to be more stable...but there are many exceptions of this rule..

okie...
there are two coordination compounds belonging to different groups.....
one is Ni(CO)₄ and the other is Co(CO)₄ dunno whether it exists or not..
so in the first one the EAN is 36 which is equal to the noble gas configuration and in the second case EAN is 35 which is not equal to the noble gas config..
so in terms of stability we find that Ni(CO)₄ is more stable than Co(CO)₄ ....coz it satisfies the noble gas config...

Now suppose in the above question if we were asked to compare b/w
PtCl₄^2- and HgCl₄^2- ..
acc. to EAN rule the answer will be HgCl₄^2-