Johann Wolfgang Dobereiner discovered that the properties of liquid Bromine lie between the properties of which gas and solid Iodine?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. Chlorine.
Johann Wolfgang Döbereiner, a German chemist, discovered in the early 19th century that the properties of liquid bromine lie between those of gaseous chlorine and solid iodine. This observation led to his concept of “triads,” where elements with similar chemical properties were grouped in threes, and the atomic mass of the middle element was roughly the average of the other two. The chlorine–bromine–iodine triad became one of the earliest examples demonstrating periodic relationships among elements, paving the way for the modern Periodic Table.