The correct order of basicity of oxides of vanadium is

How are transition metals and their oxides used in industrial processes?

All $Cu(II)$ halides are known,except the iodide. The reason for this is that:

Addition of high proportions of manganese makes steel useful in making rails of railroads,because manganese

Which pair of compounds contains both metals in their highest possible oxidation state?

Give examples and suggest reasons for the following features of the transition metal chemistry:
$(i)$ The lowest oxide of transition metal is basic,the highest is amphoteric/acidic.
$(ii)$ $A$ transition metal exhibits highest oxidation state in oxides and fluorides.
$(iii)$ The highest oxidation state is exhibited in oxoanions of a metal.