12 Questions
Which lanthanoid metal is described as steel hard?
Samarium
Why do many trivalent lanthanoid ions exhibit coloration?
Attributed to the presence of f electrons
Which lanthanoid ions are paramagnetic?
Yb2+ and Lu3+
What is the approximate first ionization enthalpy of the lanthanoids?
600 kJ mol–1
Which lanthanoid metal has a melting point significantly higher than others?
Samarium
What imparts a certain degree of stability to empty, half-filled, and completely filled f orbitals?
Exchange enthalpy considerations
Which statement best describes the trend in reactivity of actinoids as the atomic number increases?
Actinoids become less reactive as the atomic number increases.
What is the primary reason for the actinoid contraction across the series?
Strong shielding by 5f electrons
Why is it considered unsatisfactory to review the chemistry of actinoids solely based on oxidation states?
The actinoids have unpredictable oxidation states that vary greatly among elements.
How do the actinoid metals compare to lanthanoid metals in terms of appearance?
Actinoid metals are all silvery like lanthanoid metals.
Which factor contributes to the structural variability of actinoid metals?
Irregularities in metallic radii
Why do actinoids resemble lanthanoids in having more compounds in +3 state than +4 state?
+3 and +4 ions tend to hydrolyze which limits the formation of compounds with these oxidation states.
Test your knowledge on the characteristics of lanthanoid elements, including their appearance, hardness, melting points, structures, and conductivity. Learn about the unique properties of these elements and their behavior in different conditions.
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