Question

which of the following elements does not exhibit variable valency?
(a)Iron
(b)mercury
(c)lead
(d)potassium​

Answer 1

Answer:

D

Explanation:

Potassium is a element on IA and by the rules of oxidation no IA elements always have Oxiartion no 1 and OXiadtion no is the charge of that element

so answer is d and in elemental form oxidation no of k will be 0