HSC Science (Computer Science) 12th Board ExamMaharashtra State Board
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# Write Four Points of Distinction Between Lanthanoids and Actinoids. - HSC Science (Computer Science) 12th Board Exam - Chemistry

#### Question

Write four points of distinction between Lanthanoids and Actinoids.

#### Solution

 Lanthanoids Actinoids 1 In lanthanoids, last differentiating electron occupies 4f orbital In actinoids, last differentiating electron occupies 5f orbital. 2 They are the elements of first inner transition series They are the elements of second inner transition series 3 They are present in period 6 They are present in period 7. 4 Most of lanthanoids (with exception of promethium) occur in nature. Most of actinoids (with exception of uranium and thorium) are prepared in laboratory 5 Most of lanthanoids (with exception of promethium) are non-radioactive All the actinoids are radioactive. 6 Lanthanoids do not form oxo cation. Actinoids form oxo cation such as 22UO_2^(2+) , PuO2+, UO+. 7 4f orbitals in lanthanoids have higher binding energy 5f orbitals in actinoids have lower binding energy. 8 Contraction in atomic and ionic radii is relatively less in lanthanoids. Contraction in atomic and ionic radii is relatively greater in actinoids due to poor shielding of 5f electrons. 9 Lanthanoids show +2, +3 and +4 oxidation states. Actinoids show +3, +4, +5, +6, +7 oxidation states 10 Lanthanoids have less tendency to form complexes Actinoids have greater tendency to form complexes 11 Some ions of lanthanoids are coloured. Most of the ions of actinoids are deeply coloured 12 Lanthanoid hydroxides are less basic in nature. Actinoid hydroxides are more basic in nature.

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#### APPEARS IN

2015-2016 (July) (with solutions)
Question 6.3 | 2.00 marks
Solution Write Four Points of Distinction Between Lanthanoids and Actinoids. Concept: F-block Elements - The Lanthanoids.
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