Consider the elements : Cs, Ne, I and F

Consider the elements : Cs, Ne, I and F
(i) Identify the element that exhibits only negative oxidation state.
(ii) Identify the element that exhibits only positive oxidation state.
(iii) Identify the element that exhibits both positive and negative oxidation states.
(iv) Identify the element which exhibits neither the negative nor does the positive oxidation state.

(i) F exhibits only negative oxidation state because it is the most electronegative element.
(ii) Cs exhibits only positive oxidation state because it is the most electropositive element.
(iii) I exhibits both positive and negative oxidation states. Iodine exhibits — 1, 0, +1, 3, + 5 and + 7 oxidation states (+ 3, + 5 and + 7 oxidation states are exhibited by I due to the presence of vacant d-orbitals).
(iv) Ne is an inert gas, so it neither exhibits negative nor positive oxidation states.