d and f BLOCK ELEMENTS

What is the primary difference between Mendeleev's and Newlands' approaches to element classification?

• Mendeleev used atomic number, Newlands used atomic weight
• Mendeleev focused on a general periodic law, while Newlands focused on a specific octave pattern
• Mendeleev worked with fewer elements than Newlands
• Mendeleev ignored physical properties, Newlands emphasized them

What crucial aspect of Meyer's work provided empirical support for the Periodic Law?

• Predicting the properties of new elements
• Arranging elements in a tabular form
• Discovering new elements
• Graphing physical properties against atomic weight to show periodic trends

Based on the provided text, what was the main reason Newlands' Law of Octaves failed for elements beyond Calcium?

• He ran out of elements to classify
• He used incorrect atomic weights
• He did not consider noble gases
• The periodic pattern of properties broke down for heavier elements

What specific limitation of Dobereiner's triads made scientists skeptical?

• It required fractional atomic weights
• It placed elements in the wrong order
• It applied accurately to only a small number of element groups
• It contradicted the law of conservation of mass

Why is de Chancourtois's contribution often overlooked compared to Mendeleev's?

• His model was completely wrong
• He plagiarized Mendeleev's work
• His model was three-dimensional and his publication used unfamiliar geological terms
• He only worked with metals