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 exhibit both positive and negative oxidation states
d) Identify the element which neither exhibit the negative nor does the positive oxidation state.

Explanation

a) F exhibit only negative oxidation state because it is the most electronegative atom.
b) Cs exhibit only positive oxidation state because it is the most electropositive element.
c) I can exhibit both positive and negative oxidation states. Ex : In `ICl_(3)` the oxidation state of I is +3 and in NaI oxidation state of I is -1.
d) Ne being inert gas do not participate in reactions. So it will not exhibit neither the negative nor the positive oxidation states.