Question

According to Dobereiner,________?

• A. the sum of atomic masses of the first and the third elements of the triad is equal to that of the second element
• B. the sum of atomic masses of the first and the second elements of the triad is equal to that of the third element
• C. the arithmetical mean of the atomic masses of the first and the third elements of the triad is equal to that of the second one
• D. the arithmetical mean of the atomic masses of the second and the third elements of the triad is equal to that of the first

Answer 1

Answer:

C. the arithmetical mean of the atomic masses of the first and the third elements of the triad is equal to that of the second one

• The arithmetic mean of the atomic masses of the first and the third elements of the triad is equal to that of the second one.

• The statement "The arithmetic mean of the atomic masses of the first and the third elements of the triad is equal to that of the second one" is the core of Döbereiner's Law of Triads.

• In the early 19th century, German chemist Johann Wolfgang Döbereiner observed that certain groups of three elements (which he called triads) showed similar chemical properties.

• He also noticed a peculiar relationship between their atomic masses: the atomic mass of the middle element in a triad was approximately the arithmetic mean of the atomic masses of the first and the third elements.