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Explain actinoid contraction |
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Answer» Solution :In actinoid series, there is over all decrease in the ionic radii (`M^(3+)` ions) and atomic radii ACROSS the series with the increase in atomic number. This is known as actinoid contraction. Moving across the series, with the increase in atomic number, the electrons are ADDED successively in 5f- orbital and nuclear charge increases. As one electron in 5f is not effective in sheilding ANOTHER electron, the effective nuclear charge experienced by 5f electrons increases which cause in REDUCTION of size of atom or ion. This is known as actinoid contraction. As compared to lanthanoids, the contraction is more in actinoid because the 5f orbital have poorer sheilding effect than 4f orbitals (in lanthanoids). Hence effective nuclear charge experienced by electrons in CASE of actinoids is more |
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