100 Nano-Stories: Oxidation!
Episode #54: Carbon’s States Of Oxidation Explained!
Preface! ✨
It’s your favorite material science & nanotechnology enthusiast! Yesterday, I introduced how to read an element on the Periodic Table of Elements!
This article is recommended to read before proceeding to this one, reader!
However, the main point that I want to cover in the previous article is Oxidation!
Oxidation is the number of electrons of an atom in a chemical compound that was lost or gained via the process known as oxidization. This number is known as the Oxidation Number!
But let’s briefly go more into depth on Oxidation before figuring out how to solve it!
Oxidation Explained! 💡
Fundamental Concepts! 🔑
Because we have been focusing on organic chemistry in this series, we must focus on carbon as our example! So let’s go over some fundamental concepts!
The potential oxidization states of carbon are the numbers (-4, -2, +2, +4). If it has a negative number, it means that the carbon element has gained electrons from another element, and if it has a positive number, it means that the carbon element has lost electrons from another element. These are not all of the potential oxidation states of carbon, but they are the most common oxidization states for carbon to be in aerogel technologies!
In Aerogel, most of the compounds we will encounter are neutral. Neutral compounds must have all of the oxidation numbers add up to zero.
Because Aerogels will encounter water, let’s briefly focus on the oxidation of hydrogen and oxygen. Oxygen will have an oxidation state of -2. Hydrogen chemically bonded with nonmetals will have an oxidation state of +1, and hydrogen chemically bonded with metals will have an oxidation state of -1.
Finally, the elements in Group 5A will have an oxidation state of -3. The elements in Group 6A will have an oxidation state of -2. The elements in Group 7A will have an oxidation state of -1.
Carbon Oxidation States Examples! 🔑
To calculate the oxidation state of any organic molecule/compound, you find the number of valence electrons of carbon minus the valence electrons from other atoms attached to carbon (in the diagram given).
Now that we know this rule, let’s start with an easy one: Methane (CH4)! No jokes here, btw! 😂
So what is the oxidation state of methane? Well, we know that this is a neutral compound because there are no unstable atoms in methane, and neutral compounds must equal Zero!
But what is the oxidization number for Carbon in Methane?
From the essential rules, we know that Hydrogen has an oxidation state of +1 on nonmetals, and Carbon is a nonmetal. Since there are 4 hydrogen atoms attached to methane, the oxidization of the hydrogen atoms is +4.
But we need the molecule to equal an oxidation number of Zero, and we currently have +4. So that means that the only way to reach an oxidation number of 0 is that the Carbon atom must have an oxidization number of -4.
4 (hydrogen) -4 (carbon) = 0 oxidization. So Carbon has an oxidation number of -4 in methane (CH4)! 😄
For our next example, let’s use formic acid (CH2O2)!
Oxygen has an oxidation state of -2, and hydrogen has an oxidation state of +1 because it is around a nonmetal like carbon.
Because there are two oxygen atoms and two hydrogen atoms, the oxidation state of the oxygen atoms is -4, and the oxidation state of the hydrogen atoms is +2.
However, you may already have guessed that carbon’s oxidation number must equal +2 to reach the neutral compound number of Zero (which is correct).
However, to make sure, we can check our answer via electronegativity! This works by finding all the electronegativity values of the atoms in a molecule. If the electronegativity number of an atom attached to the carbon atom is higher than the carbon electronegativity (2.55), the valence electrons go to the other atom.
If the electronegativity number of an atom attached to the carbon atom is lower than the carbon electronegativity (2.55), the valence electrons go to the carbon atom. Here is a demonstration of that:
The dots mean the number of electrons that are up for grabs for carbon to potentially snatch, similar to ionic bonds. Oxygen has a higher electronegativity number than carbon, so carbon can’t grab those electrons (the color is highlighted in magenta). But it can grab the electrons from hydrogen because the electronegativity number of hydrogen is lower than the electronegativity number of carbon (the color is highlighted in green). Two electrons are in the bond between carbon and hydrogen, which means that
In the end, to calculate the oxidation states:
4 (O2 atoms) +2 (H2 atoms) +2 (C atom) = Zero Oxidation Number!
And we’re done, reader! Oxidation states complete! 🎉
Closing Thoughts! 💭
Now we understand how to solve the value between oxygen atoms and their behavior for the upcoming transparent aerogel research!
See you tomorrow to finally start our transparent aerogel knowledge dives! 😉
Vocabulary! 📓
Valence Electrons → Electrons in the outer shell/last row of an atom.
Electronegativity → The chance that a pair of elections will be attached to a certain atom. If the difference between the electronegativity is greater or equal to 0.5, the molecule is polar. If the difference in electronegativity in the molecule is less than 0.5, the molecule is non-polar. Covalent bonds occur at an electronegativity below around 1.7, and ionic bonds occur at an electronegativity equal to or greater around 1.7.
Covalent bonds → They are chemically bonded because the electrons are being shared evenly! Covalent bonds form between two nonmetals! Sharing is caring! 😄
Ionic bonds → Giving away an electron to another atom to stabilize their outer electron shell. Ionic bonds form between a metal and a nonmetal. So you could say that ionic bonds give away/steal their electrons! 😂
Oxidation → The number of electrons of an atom in a chemical compound that was lost or gained via the process known as oxidization. This number is known as the Oxidation Number!
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