Single Choice

$$K^{+}$$ and $$Cl^{-}$$ ions are isoelectronic. Which of the following statements is not correct?

ABoth $$K^{+}$$ and $$Cl^{-}$$ ions contain 18 electrons.
BBoth $$K^{+}$$ and $$Cl^{-}$$ ions have the same configuration.
C$$K^{+}$$ ion is bigger than $$Cl^{-}$$ ion in ionic size.
Correct Answer
D$$Cl^{-}$$ ion is bigger than $$K^{+}$$ ion in size.

Solution

$$K^+$$ is a cation and therefore will be smaller in size as compared to an isoelectronic neutal atom or an anion like $$Cl^-$$
This is because of higher effective nuclear charge experienced by the valence electron in a cation.
Number of electrons in $$K^+$$:Z-1=19-1=18: $$1s^22s^22p^63s^23p^6$$
Number of electrons in $$Cl^-$$:17+1=18: $$1s^22s^22p^63s^23p^6$$
option C

SIMILAR QUESTIONS

Chemical Bonding

Which of the following arrangements represents the increasing order (smallest to largest) of ionic radii of the given species $$O^{2-}, S^{2-}, N^{3-}, P^{3-}$$?

Chemical Bonding

The ionic radii (in $$\mathring{A}$$) of $$N^{3-}$$, $$O^{2-}$$ and $$F^{-}$$ are respectively :

Chemical Bonding

The increasing order of the ionic radii of the given isoelectronic species is:

Chemical Bonding

The correct order of decreasing ionic radius among the following anions would be:

Chemical Bonding

Which of the following have the largest ionic size?

Chemical Bonding

The species $$Ar, K^+$$ and $$Ca^{2+}$$ contain the same number of electrons. In which order do their radii increase?

Chemical Bonding

What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (i) F$$\displaystyle ^{-}$$ (ii) Ar (iii) Mg$$\displaystyle ^{2+}$$ (iii) Rb$$\displaystyle ^{+}$$

Chemical Bonding

The size of isoelectronic species $$F\displaystyle ^{-}$$, $$Ne$$ and $$Na\displaystyle ^{+}$$ is affected by :

Chemical Bonding

Which one of the following groups represents a collection of isoelectronic species? (At. nos.: Cs-55, Br-35)

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