Question

arrange these ions according to ionic radius.
largest radius
rb+
sr²+
as³-
se²-
br-
smallest radius
answer bank

Explanation:

Ionic radius trends: For isoelectronic species (same number of electrons), the more negative the charge, the larger the ionic radius (due to less effective nuclear charge pulling electrons in), and the more positive the charge, the smaller the ionic radius. \(As^{3 - },Se^{2 - },Br^{ - },Rb^{ + },Sr^{2 + }\) are isoelectronic (all have 36 electrons).

Answer:

Largest radius: \(As^{3 - }\), then \(Se^{2 - }\), then \(Br^{ - }\), then \(Rb^{ + }\), smallest radius: \(Sr^{2 + }\)