how to identify whether a d block compound is acidic or basic or amphoteric based on oxidation number

@ sashi 
the nature of the compound can be determined by the oxidation number , 
acc to the arrhenius concept of lewis and bases , the compound which can donate proton is called an acids and the compound which can accept the proton ios called as bases , so, by oxidation number if the o.n is on +ve then most probably its acidic and in the o.n is -ve then its basic , 
otherwise u can check by the ph value also if that is given , otherwise go with the block trends , like acidic charecter increase down the group and from that u can compare the compound which is top of the group will be besic , 
HOPPE IT CLEARS YOUR DOUBT