Question

write the Properties of Actinoids

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Answer 1

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i. Similar to lanthanoids, they appear silvery white in colour.

ii. These are highly reactive radioactive elements

iii. Except promethium (Pm), all are non-radioactive in nature

iv. They experience decrease in the atomic and ionic radii from actinium (Ac) to lawrencium (Lw), known as actinoid contraction

v. They usually exhibit +3 oxidation state. Elements of first half of the series usually exhibit higher oxidation states.

Answer 2

Answer:

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Characteristics

⏩Actinoids are typical metals. All of them are soft and have a silvery colour which tarnishes in air.

⏩They have relatively high density and plasticity. Some of them can be cut with a knife.

⏩All actinoids are radioactive, paramagnetic with the exception of actinium, have several crystalline phases.

All actinoids are pyrophoric, especially when finely divided, that is, they spontaneously ignite upon reaction with air.

⏩Together with radium and transuranic elements, actinium is one of the most dangerous radioactive poisons. The real danger with the actinoid elements lies in the radioactive properties of these elements. They are emitters of tissue-destroying and cancer producing rays (alpha, beta, or gamma radioactivity). Actinium can accumulate and remain in the surface layer of skeletons. Less than one-millionth of a gram of some actinoid isotope can be fatal.

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