Polarizability

[Maggie Doan 1I]

Which one has higher polarizability?
a) Be 2+ or Li 1+
b) Mg 2+ or Be 2+

I tried using the ideas of the polarizability trend but it didn't work.

[rikolivares]

I think that when ions have the same number of electrons, you go with the atom that has the largest atomic radius as the atom with the lowest polarizability.

[705137650]

Polarizability is the ability to form instantaneous dipoles. It is a property of matter. Polarizabilities determine the dynamical response of a bound system to external fields, and provide insight into a molecule's internal structure.

[2c_britneyly]

Li+ and Mg2+ have higher polarizabilities, respectively.

In (a), both Li+ and Be2+ have the same number of electrons. However, because Be 2+ has more protons, there is a higher nuclear charge, and electrons are drawn in more closely, making the cation smaller and not as likely to lose electrons. Li+ has one less proton;therefore, its nuclear charge is not as strong, so the electrons aren't drawn in as strongly to the nucleus.

In (b), Mg2+ has more electrons than Be2+, so we know its electrons will not be drawn in as effectively due to shielding. Electrons in the outer shells of the Mg2+ are more likely to be pulled away.