Skip to main content
Ch.7 - Periodic Properties of the Elements
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Non è quello che usi tu?Cambia libro di testo
Capitolo 7, Problema 35

Provide a brief explanation for each of the following: (a) Cl- is larger than Ar. (b) P3- is larger than S2-. (c) K+ is larger than Na+. (d) F- is larger than F.

Guida verificata passo dopo passo
1
Consider the position of K and Na in the periodic table. K (potassium) is located in period 4, while Na (sodium) is in period 3.
Understand that as you move down a group in the periodic table, the number of electron shells increases. This means K has more electron shells than Na.
Recognize that both K+ and Na+ ions have lost one electron compared to their neutral atoms, resulting in the same electron configuration as the noble gas preceding them.
Despite having the same electron configuration, K+ has more electron shells than Na+, making it larger in size.
Conclude that the increase in the number of electron shells as you move down a group results in a larger ionic radius for K+ compared to Na+.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
2m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Ionic Radius

Ionic radius refers to the size of an ion in a crystal lattice. Cations, like K<sup>+</sup> and Na<sup>+</sup>, are formed when atoms lose electrons, resulting in a decrease in size due to reduced electron-electron repulsion and increased effective nuclear charge. The ionic radius can vary based on the ion's charge and the number of electron shells.
Video consigliato:

Periodic Trends

Periodic trends are patterns observed in the properties of elements across the periodic table. As you move down a group, the ionic radius increases due to the addition of electron shells, which outweighs the increase in nuclear charge. This explains why K<sup>+</sup>, located below Na<sup>+</sup> in Group 1, is larger.
Video consigliato:
Percorso guidato
00:38
Periodic Trends

Effective Nuclear Charge

Effective nuclear charge (Z<sub>eff</sub>) is the net positive charge experienced by an electron in a multi-electron atom. It accounts for the shielding effect of inner electrons. In the case of K<sup>+</sup> and Na<sup>+</sup>, although both are cations, K<sup>+</sup> has more electron shells, leading to a larger ionic radius despite a similar Z<sub>eff</sub>.
Video consigliato:
Percorso guidato
01:51
Effective Nuclear Charge