ALCH-201 Lessons

 Lesson 9 - On the Atomic Level

Objectives:

• Have a basic understanding of naming a binary molecular compound.
• Learn the brief history behind alchemical nomenclature.

Welcome to the last class of the course! As you may know, your final is today, although not a lot of you seem too thrilled about it. Don’t worry, I believe in each and every one of you and I am confident that you will succeed! Before you open your final, make sure to review the material in the previous lessons. If there is anything you don’t understand about the course material, be sure to ask a PA, Head Student, or myself before taking the exam.

Now, what exactly are we talking about today? We will be going over chemical nomenclature of binary molecular compounds. Chemical nomenclature is a list of rules to name chemical compounds. This subject may seem a tad dull and it will not be included in your final, however, do expect it on your O.W.L.s when they come along.

While this may not seem very important, we do look at certain chemicals in the laboratory, so you need to know how to look at a name for a chemical and determine how many atoms of whichever elements are in the compound. Even though this is typically used in the Muggle world, alchemists need to be able to understand how to use and analyze chemical nomenclature. Modern chemistry is the Muggles’ successor to alchemy, so their findings can often be applicable to our own findings. The most common system used today was developed by the Muggle organization, the International Union of Pure and Applied Chemistry (IUPAC). The IUPAC is a federation established in 1919 that represents chemists internationally and is best known for standardizing nomenclature.

Why do we need chemical nomenclature? Well, the main purpose of having nomenclature is to ensure that there is no uncertainty about what makes up a chemical compound. Fun fact, early nomenclature in alchemy was aimed towards making everything cryptic, rather than easy to understand like modern nomenclature. They were often rich in description and that was so it would be harder for the general public to interpret someone’s findings. What do I mean by that? Well, let’s say you read the word “Mercury” in someone’s alchemical journal. With little to no context, could you tell me if the alchemist was talking about the planet, the metal, or the prime? More than likely, no. Modern Muggle chemists say that this was one of the biggest flaws in alchemy, when in reality it was a way to create an extra wall of secrecy between alchemists and non-alchemists.

Now that we got that out of the way, let’s look at binary molecular compounds. Binary molecular compounds are compounds made up of two non-metal elements. These are the easiest compounds to name. There is also a Periodic Table of Elements above if you need to reference anything. It may look a little squished so here’s the link to it as well. Here are a few rules to remember when you’re naming a binary molecular compound:

• The atom with the most positive charge always comes first.
• The negative atom, which comes second, always has the suffix “-ide.”
• Each prefix in the chart below indicates how many atoms are in the compound.

Let’s take a look at a few examples!

CO2 - Carbon Dioxide

As you can see on the periodic table, carbon is “C” and oxygen is “O.” The name “Carbon Dioxide” refers to there being one carbon atom and two oxygen atoms. Due to carbon having not as many electrons as oxygen, it’s first in the nomenclature. Since there are two oxygen atoms in the compound, the prefix “Di-” is needed. Also, because oxygen is the more negatively charged of the two, it is at the end of the nomenclature, so you will need to add the suffix “-ide.” On a quick note, the number of electrons an atom has is generally the same as the number of protons. The atomic number of the element on the periodic table indicates the number of protons in the atom.

P4S5 - Tetraphosphorus Pentasulphide

Here is a more complicated example of naming a binary molecular compound. This compound contains four atoms of Phosphorus (P) and five atoms of Sulphur (S). Looking at the prefixes listed in the chart and the different elements in the nomenclature, you can easily figure out how to write the chemical formula.

Of course, this subject of chemical nomenclature can be pretty lengthy and complex. As you still need to take your final, I won’t go further than this basic understanding of it. However, if you would like to learn more about chemical nomenclature and how to name more complex compounds, the MuggleNet is your ocean of knowledge. Now that we have gotten that out of the way, we are ready to start the final! I wish you good luck and congratulations for completing Alchemy 201!