Question

A group of three elements with similar physical and chemical properties is called ------------

Answer 1

Explanation of Dobereiner’s triads:

• Dobereiner arranged three elements with similar chemical properties in a group called triads.
• According to him, the atomic weight of the middle element is the average atomic weight of the other two elements.

Example:

Li (Lithium), Na (Sodium), and K (Potassium) form a triad.

Atomic weight of Na = (atomic weight of Li + atomic weight of K) / 2 = (7+39)/2 =46/2 =23