Deduce which of the following species has the largest ionic radius.S2−F−Al3+Mg2+

The ionic radius is influenced by several factors including the atomic radius, the charge of the ion, and the electron configuration.

1. Atomic Radius: In general, the atomic radius increases as you move down a group on the periodic table and decreases as you move across a period from left to right.

2. Charge: Anions (negatively charged ions) are larger than their parent atoms because the addition of electrons increases electron-electron repulsion, causing the electron cloud to expand. Cations (positively charged ions) are smaller than their parent atoms because the loss of electrons decreases electron-electron repulsion.

3. Electron Configuration: Ions that have a completely filled electron shell are generally smaller due to the increased stability and decreased repulsion.

Now, let's apply these principles to the ions given:

• S2-: Sulfur is in the 3rd period and 16th group of the periodic table. It has gained 2 electrons to achieve a stable electron configuration, making it an anion.

• F-: Fluorine is in the 2nd period and 17th group. It has gained 1 electron, making it an anion.

• Al3+: Aluminum is in the 3rd period and 13th group. It has lost 3 electrons, making it a cation.

• Mg2+: Magnesium is in the 3rd period and 2nd group. It has lost 2 electrons, making it a cation.

Comparing the ions, we can see that S2- and F- are anions and will be larger than Al3+ and Mg2+ which are cations. Between S2- and F-, S2- is in a lower period and has gained more electrons, so it will be larger. Therefore, S2- has the largest ionic radius.