Ionic Compounds and Radii Quiz

Questions and Answers

What is the primary reason a cation is smaller than its parent atom?

It has a lower nuclear charge.

It gains additional protons.

It has fewer electrons with the same nuclear charge. (correct)

It has more electrons than the parent atom.

Which statement about anions is true?

Anions are formed by losing an electron.

Anions have a higher effective nuclear charge.

Anions are always smaller than their parent atoms.

Anions will have a larger size due to increased electron repulsion. (correct)

What do isoelectronic species have in common?

They exhibit identical ionic radii.

They have the same number of neutrons.

They have the same number of electrons. (correct)

They have the same number of protons.

How does the ionic radius of fluoride ion (F) compare to that of its parent atom?

<p>It is larger than the atomic radius of fluorine.</p> Signup and view all the answers

What trend is observed in the ionic radii of elements compared to their atomic radii?

<p>Ionic radii exhibit the same trend as atomic radii.</p> Signup and view all the answers

Study Notes

Ionic Formation and Radii

Removal of an electron from an atom forms a cation, while the addition of an electron forms an anion.
Ionic radii can be estimated by measuring distances between cations and anions in ionic crystals.
Ionic radii generally follow the same trend as atomic radii.

Size Comparison of Ions and Atoms

A cation is smaller than its parent atom due to fewer electrons while maintaining the same nuclear charge.
An anion is larger than its parent atom because adding electrons increases electron-electron repulsion and decreases effective nuclear charge.

Example Ionic and Atomic Radii

Fluoride ion (F⁻) has an ionic radius of 136 pm, whereas the atomic radius of fluorine is 64 pm.
Sodium (Na) has an atomic radius of 186 pm and an ionic radius of 95 pm for Na⁺.

Isoelectronic Species

Atoms and ions with the same number of electrons are classified as isoelectronic species.
Example of isoelectronic species includes O²⁻, F⁻, Na⁺, and Mg²⁺, all containing 10 electrons.
Radii differ among isoelectronic species due to varying nuclear charges.

Charge Effects on Ionic Size

Cations with a greater positive charge exhibit smaller radii because of stronger attraction between electrons and the nucleus.
Anions with a greater negative charge show larger radii due to increased electron repulsion that overcomes nuclear charge.

Description

This quiz explores the formation of cations and anions through the gain or loss of electrons. It covers concepts like ionic radii estimation and trends in ionic and atomic sizes. Test your understanding of how these concepts relate to atomic structure and ionic compounds.