Is Al3+ Diamagnetic or Paramagnetic? Explain.

The aluminum ion, Al³⁺, is considered diamagnetic. This is primarily due to the electron configuration it possesses after losing three electrons.

When you look at the neutral aluminum atom, it has an atomic number of 13, which means it has 13 electrons. The electron configuration for aluminum is [Ne] 3s2 3p1. When aluminum loses three electrons to form the Al³⁺ ion, it loses the two 3s electrons and the one 3p electron, resulting in the electron configuration of [Ne]. This configuration indicates that Al³⁺ has no unpaired electrons. Since diamagnetism arises in materials that have all their electrons paired, Al³⁺ exhibits diamagnetic properties.

In contrast, paramagnetic substances have unpaired electrons, which create a magnetic moment that can align with an external magnetic field. Since Al³⁺ has all paired electrons, it cannot be attracted into a magnetic field like paramagnetic materials can, thus confirming its diamagnetic behavior.