Home › Maharashtra SSC (Class 10) › Chemistry › Periodic Classification of Elements › Which pair of elements created an ambiguity in t…
Which pair of elements created an ambiguity in their sequence because they share the same whole-number atomic mass?
ACalcium and strontium
BSodium and potassium
CChlorine and bromine
DCobalt and nickel
Answer & Solution
Correct answer: D. Cobalt and nickel
1. Mendeleev ordered elements by increasing atomic mass.
2. Cobalt (Co) and nickel (Ni) have the same whole-number atomic mass.
3. So their order in the table could not be decided unambiguously.
4. Rule out the other pairs, whose atomic masses differ clearly.
_Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 2 "Periodic Classification of Elements", p.29_
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 (