Question

Which of the following statements are true regarding Dobereiner's periodic table?

• A. The elements are written in the increasing order of atomic masses.
• B. Similar elements occur after an interval of seven elements.
• C. The mass of middle element was roughly the average of atomic masses of other two elements.
• D. Elements in a triad show similar properties.

Answer 1

Answer: (A), (C), (D)

The correct options are
A The elements are written in the increasing order of atomic masses.
C The mass of middle element was roughly the average of atomic masses of other two elements.
D Elements in a triad show similar properties.

Dobereiner stated that when elements with similar properties are arranged in a group of three (triad) in the increasing order of their atomic mass, the atomic mass of the middle element is roughly the average of the atomic masses of the other two elements.
However, similar elements occur at an interval of seven elements is one of the feature of Newland's octave.