Consider the elements:
`Cs, Ne, I` and `F`
a. Identify the element that exhibits only negative oxidation state.
b. Identify the element that exhibits only positive oxidation state.
c. Identify the element that exhibits both positive and negative oxidation states.
d. Identify the element which exhibits neither the negative nor does the positive oxidation state.

Explanation

(a) F exhibits only negative oxidation state of `-1` .
Cs exhibits positive oxidation state of `+1` .
(c) I exhibits both positive and negative oxidation states . It exhibits oxidation states of `-1 , +1 , +3 , +5 ` and `+7`
(d) The oxidation state of Ne is zero . It exhibits neither nor positive oxidation states .