Question

Which of the following statements is correct?

• A. $X^{-}$ ion is larger in size than X atom
• B. $X^{+}$ ion is larger in size than X atom
• C. $X^{+}$ ion is larger in size than $X^{-}$ ion
• D. $X^{+}$ and $X^{-}$ ions are equal in size

Answer 1

Answer: (A)

$X^{-}$is larger in size than $X$ atom.
Radius of anion is always greater than that of its neutral atom and positive ion.
When one or more electrons are taken up by an atom, effective nuclear charge decreases.
Electron of the outermost orbit is attracted towards the nucleus by a lesser force. Hence, radius of anion increases. Example:- Radius $\underset{1.36\mathring{A}}{F^{-}}>\underset{0.72\mathring{A}}{F}$