d and f BLOCK ELEMENTS

Based on Table 3.3, which property prediction for Eka-aluminium (Gallium) was least accurate?

• Atomic weight
• Density
• Formula of oxide
• Melting point

Which element's discovery first provided strong evidence for Mendeleev's predictions?

• Germanium
• Scandium
• Fluorine
• Gallium

What was a key factor that allowed Mendeleev to make successful predictions about undiscovered elements?

• He used advanced technology.
• He guessed randomly.
• He focused on alphabetical order.
• His focus on grouping elements with similar properties according to his Periodic Law.

How did Mendeleev's 1905 periodic table differ from his original 1869 version?

• It was based on atomic numbers.
• It was less accurate.
• It resembled the Modern Periodic Table more closely.
• It only included gaseous elements.

What does the discovery of gallium and germanium validate about Mendeleev's work?

• That his atomic weight measurements were perfect.
• That he discovered all elements.
• That his table was purely theoretical.
• The predictive power and fundamental correctness of his Periodic Law and table structure.