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AP EAMCET · Chemistry · Classification of Elements and Periodicity in Properties

Higher second ionisation enthalpies than expected are observed for

  1. A Ti, Zn
  2. B \(\mathrm{Mn}, \mathrm{Fe}\)
  3. C \(\mathrm{V}, \mathrm{Ni}\)
  4. D \(\mathrm{Cr}, \mathrm{Cu}\)
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Answer & Solution

Correct Answer

(D) \(\mathrm{Cr}, \mathrm{Cu}\)

Step-by-step Solution

Detailed explanation

The electronic configuration of \(\mathrm{Cr}\) is \([\mathrm{Ar}] 3 d^5 4 s^1\) and that of \(\mathrm{Cu}\) is \([\mathrm{Ar}] 3 d^{10} 4 s^1\). Their second ionisation enthalpies are higher than expected because after removal of one electron chromium gets a half-filled…