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

Assertion (A) \(\mathrm{Mg}^{2+}\) and \(\mathrm{Al}^{3+}\) are isoelectronic but the magnitude of ionic radius of \(\mathrm{Al}^{3+}\) is less than that in \(\mathrm{Mg}^{2+}\). Reason \((R)\) The effective nuclear charge on the outermost electrons in \(\mathrm{Al}^{3+}\) is greater than that in \(\mathrm{Mg}^{2+}\). The correct option among the following is

  1. A \(A\) is true, \(R\) is true and \(R\) is the correct explanation for A.
  2. B \(A\) is true, \(R\) is true but \(R\) is not the correct explanation for \(A\).
  3. C \(A\) is true but \(R\) is false.
  4. D \(A\) is false but \(R\) is true.
Verified Solution

Answer & Solution

Correct Answer

(A) \(A\) is true, \(R\) is true and \(R\) is the correct explanation for A.

Step-by-step Solution

Detailed explanation

Higher the electrostatic attraction between nucleus and valence electron, smaller will be the size of the atom/ion. Electrostatic attraction is given by \(Z_{\mathrm{eff}}=Z-S\) where, \(Z=\) the number of protons in the nucleus of an atom or ion (the atomic number) and \(S=\)…