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Discuss similarities and dissimilarities in properties of lanthanoids and actinoids. |
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Answer» Solution :Points of similarities: Both SHOWS oxidation state of (+3) Both shows contraction in ionic size in tripositive state along the series Both exhibit paramagnetism Both are electropositive and REACTIVE Both form COLOURED ions Points of dissimilarities: The dissimilarities in a properties of lanthanoids and actinoids is because of (i) Less binding energy of 5f electrons as compared to 4f electrons. (ii) Poorer shielding effect of 5f electrons as compared to 4f electrons. Actinoid shows large number of oxidation states (upto +7) while lanthanoids show maximum oxidation state of (+4) All actinoides are radioactive, while in lanthanoids only PROMETHIUM is radioactive Outer electrons in actinoids are easily available for bonding Oxo-anions of actinoids are KNOWN Ex: `UO_(2)^(2+)` while lanthanoid donot form oxoanions Actinoids react with non-metals at moderate temperatures while lanthanoid reacts at high temperatures. |
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