what is the geometry of [Ni(CO)4] and [Pd(Cl)4}2- ? kindly show how to do it using VBT theory step by step.

dear aakansha 
{Ni(CO)4 } is an unusual complex , it has Ni in 0 oxidation state , thus there are 8 electrons in 3d and 2 electrons in 4s , 
CO is the strongest ligand , and does cause pairing by leaving 1 empty d orbital . 
now , somehow the paired electron in 4s shift to 3d leaving 4s orbital empty and free to accomdate electron from CO . 
so, there are no free d orbital as its a weak ligand , so, it have a sp3 hybridisation meaning tetrahedral shape . 
FOR STRUCTURE U NEED TO REFER NCERT , TELL ME IN WHICH STEP U HAVE DOUBT , SO, THAT I CAN EXPLAIN THAT PERTICULAR STEP . 

hope u can do the anathor one now , 
REGARDS