Sure, curiosity killed the cat, but it did the exact opposite for the world of science. Curiosity has been the bedrock of the various sciences for hundreds of years. Without it we might never have understood light, gravity, engineering, and in particular chemistry. Chemistry is a physical science that studies the make up, design, and properties of matter. It also looks to discover changes in matter itself, on an atomic level. Without curiosity scientists might never have looked as deeply as they have into the atomic recipes that make the world … well, the world. Without the curious chemists we would not even understand what an ion is, let alone a common one! If you have a love of science and want to learn more about chemistry and ions then you should take Udemy’s chemistry course. Start with Part One: Principles of Chemistry and get your curiosity up and running.
What Exactly Is An Ion?
Before jumping into common ions, you’ll have to understand what an ion is. At its most basic an ion is merely an atom or molecule. Then why not just call it that? This is because ions are a special type of atom or molecule that has a total number of electrons (a subatomic particle that give a negative electrical charge) that is not equal to its total number of protons (which gives the atom or molecule a positive charge). For many elements in the periodic table (the scientific chart of atoms) the protons and electrons balance out, negative and positive, so that the charge of the atom is at zero or neutral. But since ions have an unequal number of electrons and protons they have different electrical charge that is either net positive or negative. Ions have been around since the dawn of time, but were only discovered in science by Michael Faraday in 1834. In the scope of history that is only a very short time we’ve had in the company of ions.
Ions are formed by chemical or physical means. In the chemical process when a neutral atom loses one or more electrons and gains a net positive charge it becomes a specific type of ion known as a cation. If atoms gain electrons and become net negative they are known as anion. This effect happens when different atoms are introduced to each other and bond ionically, thus changing the make up of the atom. Events like this happen naturally in the physical world as well. Two prime examples of ionic phenomena include the brightness of the sun’s rays as well as the ionosphere that surrounds the earth. If you’re ready to learn more about chemistry and you’ve finished part one of Udemy’s course, it’s time to move on to part 2: Chemistry of the Elements.
What About Common Ions? What Are Those?
Common ions are exactly what the name says: common. These are the atoms and molecules that already have non-neutral electricity. When notating these common ions it is important that their net positive or net negative status is listed. Adding a plus symbol (+) to cations (net positive ions) and a negative symbol (-) to anions (net negative ions) is how to correctly notate these ions. Below you’ll find a list of the basic common ions that science knows of.
- Common Simple Cations: aluminum Al3+, calcium CA2+, copper Cu2+, hydrogen H+, ferrous iron Fe2+, ferric iron Fe3+, magnesium Hg2+, mercury (II) Mg2+, potassium K+, silver Ag+, Sodium Na+.
- Common Simple Anions: chloride C–, fluoride F–, bromide Br–, oxide O2-
These are not the only common ions, however. These above are considered simple ions because they are made of single atom. When an ion is made of two or more atoms it is called a polyatomic ion. Most common cations are simply polyatomic, however the common anions are most often already combined with oxygen (which adds the suffix –ate to their name) to give them a make up of two or more atoms. The polyatomic anions that have done this are called oxoanions. Below is a list of both common polyatomic cations and common oxoanions.
- Common Polyatomic Cations: ammonium NH4+, hydronium H3O+, mercury (I) Hg22+.
- Common Oxoanions: carbonate CO32-, hydrogen carbonate HCO3–, hydroxide OH–, nitrate NO3–, phosphate PO43-, sulfate SO 42-
Still interested in learning more about chemistry? Bet you are. Time to move on to part 3 of Udemy’s Chemistry course: Organic and Physical Chemistry.
The Common Ion Effect
As you can see, ions are created when they interact with other elements. This is a natural process in life that can be recreated in a chemistry lab. When two elements are introduced to each other in a solution (be it gas or liquid) from two different sources but share a similar ion this is known as the common ion. An example here would be adding a common salt AgNO3 to a solution of silver chloride, notated as AgCl. Both of these chemical compounds contain a common ion, which is Ag or silver. Another example would be adding both sodium chloride NaCl and Silver Chloride AgCl to a third solution. Here the Chloride is the common ion because both compounds had it when they were added to the third.
The common ion effect is often used to create a reaction to restore equilibrium when it has become unbalanced. In this case the balance shifts towards the reactants restoring order to the chemical compounds. This all relates to Le Chatelier’s Principle, also known as ‘The Equilibrium Law,’ which states that the ions in excess will combine with the oppositely charged ions and thus restore the balance. In more simple terms the common ion effect is explained as the withholding of the disassociation of a less strong electrolyte that contains the common ion. In the most basic cases this is explained by examining the solubility of salt in a solution that contains a common ion with the salt, such as the example above.
A prime example of the common ion effect in every day life concerns the adjustment of drinking water through the solubility effect. When drinking water is taken from chalk or limestone aquifers it can contain far too many minerals and become difficult to drink. This is known as ‘hard water.’ In order to reduce the hardness of the water a common ion is added during the water treatment process in order to affect the equilibrium. Often sodium carbonate salt, NA2CO3,is added to the water in order to precipitate out the calcium carbonate CACO3. Taking a look at the annotations of the two different elements it is not hard to see what the common ion is here: carbonate.
Another type of common ion effect is the buffering affect. This is used when the pH balance (acidic level) need to be adjusted in a buffer solution. An example here is when sodium acetate – CH3COONa – and acetic acid – C2H4O2 – are both dissolved in the same solution. Because the sodium is a particularly strong electrolyte it dissolves in the solution completely. The acetic acid on the other hand is a weak acid so it only dissolves (or ionizes) slightly. However, because of Le Chatelier’s Principle the addition of the sodium acetate will overpower the weak acid and decrease the pH.
Chemistry is a fascinating subject and by exploring ions, common ions, and the common ion effect, and net ionic equations it is possible to learn a great deal about how the organic world works. If you’re ready then it’s time to step into part 4 of Udemy’s chemistry course called Chemistry in Society. Chemistry can open a door to a fascinating world and if you’re curious about learning then you’re already on the right track to a great scientific education with Udemy!