Which is not an essential elements for plants?

Solution (By Examveda Team)

Sodium is not an essential element for plants among the given options whereas all the other elements like Iron, Potassium, and Zinc are under 17 essential elements required for proper growth and development of plants.
Sodium is not an essential element for plants but can be used in small quantities, similar to micronutrients, to aid in metabolism and synthesis of chlorophyll.