Home › Maharashtra SSC (Class 10) › Chemistry › Periodic Classification of Elements › In Dobereiner's triads, the atomic mass of the m…
In Dobereiner's triads, the atomic mass of the middle element is approximately equal to which value?
AThe mean of the atomic masses of the other two elements
BThe sum of the atomic masses of the other two elements
CThe product of the atomic masses of the other two elements
DThe difference of the atomic masses of the other two elements
Answer & Solution
Correct answer: A. The mean of the atomic masses of the other two elements
1. Dobereiner grouped elements with similar properties in threes.
2. He arranged each triad in increasing order of atomic mass.
3. The middle element's atomic mass is about the mean (average) of the first and third.
4. Example: for Li(6.9), Na(23.0), K(39.1), mean $= \frac{6.9 + 39.1}{2} = 23.0$, matching Na.
_Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 2 "Periodic Classification of Elements", p.25_
Related questions
A solid salt crystal will not conduct electricity, but the same salt dissolved in water wiWhat actually holds a piece of metal together in metallic bonding?What happens to electrons when an ionic bond is formed?In which type of bonding are pairs of electrons shared between atoms?The property of attracting shared electrons by halogen atoms in a molecule is called:In cathodic protection against corrosion, the metal that is deliberately attached to corroWhy does dilute or concentrated nitric acid fail to react vigorously with aluminium metal?During the smelting of iron in the blast furnace, what is the main role of the limestone (