Question

Transition elements show positive oxidation state, generally, due to:

• A. large atomic size
• B. low ionization energy
• C. low electronegativity
• D. high electronegativity

Answer 1

The correct option is B low ionization energy

Mostly because the electronegativity of these elements is pretty low and to get a negative oxidation number you’d have to let them react with something that is even less electronegative, say potassium or caesium.

Such compounds may well exist but they usually have metallic bonding and that makes it hard to distinguish oxidation states because these darned electrons keep running around instead of sitting on any atom in particular. Chemists often discard such compounds by calling them ‘alloys’ as if that solves everything.

There is an exception to this story though and that is one of the last transition elements: gold. Its electronegativity is pretty high, about 2.54 which is about the same as selenium. With alkali metals, it does form aurides that are not very conductive and gold is in a -1 oxidation state.

Hence, the correct option iss $B$