Name the German chemist who grouped elements into triads in 1817.

Correct option is C

Ans. (c) Johann Wolfgang Döbereiner

Sol.Johann Wolfgang Döbereiner, a German chemist, introduced the concept of triads in 1817 as an early attempt to classify elements. He observed that certain groups of three elements had similar chemical properties and that the atomic weight of the middle element was approximately the average of the other two. This arrangement is known as Döbereiner’s Triads and was an important step in the development of the modern periodic table.

Information Booster:

• Döbereiner’s Triads were based on similarities in atomic mass and chemical properties.
• Examples of triads:
  • Lithium (Li), Sodium (Na), Potassium (K)
  • Calcium (Ca), Strontium (Sr), Barium (Ba)
  • Chlorine (Cl), Bromine (Br), Iodine (I)
• His work helped establish the periodic classification of elements.
• Although limited in scope, it influenced later periodic table developments.
• The concept of periodicity in chemistry evolved from Döbereiner’s findings.
• His classification was later expanded upon by scientists like Newlands and Mendeleev.

Additional Information:

• (a) Dmitri Ivanovich Mendeleev – Developed the modern periodic table in 1869, organizing elements based on atomic mass and predicting undiscovered elements.
• (b) John Newlands – Proposed the Law of Octaves in 1864, which stated that every eighth element showed similar properties.
• (d) Henry Moseley – Discovered that atomic number (not atomic mass) determines an element's properties, leading to the modern arrangement of the periodic table.