Could the halide ions (fluoride, chloride, bromide and iodide) be used in the same applications as the noble gases?


After all the halide ions have the same electron configuration as the noble gases, so they should have similar properties…

In: 2

Well, no, because they’re now ions. They have a net negative charge which means they are going to be fairly reactive with respect to positively charged ions whereas noble gases would be inert.

A halide ion has a negative charge as it has one less proton in the nucleus. Even though the electron configuration is the same as the adjacent noble gas. So its going to react differently.

Chiefly it’s going to pair up with any positive ions around. Additionally, although not fully ionized, many molecules have centres with more or less electrons than the formal sharing picture would suggest. Water, for instance, has an oxygen atom which drags in a little more than its fair share, leaving the hydrogens with a small deficit and therefore a small positive charge. The picture of ions as lone F^- Cl^- and so on is very much a simplification particularly when solvents are concerned.

They’re similar in that they’re no longer aggressively attempting to strip electrons from other atoms, but they’re also now electrically charged and will participate in all sorts of ion-exchange reactions.

You’re also trying to handle *just negative ions* which isn’t really possible. They need a charge balance or the tremendous electrostatic repulsion between ions will start to blow stuff up.

Noble gases are unique because they’re highly stable structurally *and* electrically neutral.