 Hey everybody, Dr. O here. So let's talk about ions. So most atoms exist in a form like you see on the left, the sodium atom that has the same number of protons and electrons. So they're electrically neutral, same number of positive and negative charges. But atoms will often become ions if they're trying to fill their outer electron shell by either giving up electrons or receiving electrons. If an atom loses a negative electron like this one here, it is now an ion and it has a positive charge making it a cation. If an atom gains an electron, it will now have a negative charge because it has more negative electrons than it has positive protons. That will be a negative ion also known as an anion. So let's go ahead and look at an example of this happening. This is going to be an ionic bomb, but we'll also talk about the other reasons that ions are important. So here's sodium. We're only looking at valence shell electrons here, the outer shell. So you don't see the inner shells here. Sodium has that one electron. It has two options. If it wants to complete an octet and fill that outer shell, it either needs to gain seven electrons or lose one, much easier to lose one. So sodium is going to be made happy by giving up an electron. That chlorine has seven electrons. It can only be happy by giving up seven or gaining one. Obviously gaining one makes the most sense. So sodium wants to give up an electron. Chlorine wants to gain an electron. Once that happens, sodium is now a positive cation. Chlorine is now a negative chloride anion, sorry, and they now have opposite charges, which is why they often will stay close together because they will form an ionic bond. It's caused by that transfer of electrons because opposites attract. But in biological fluids, most of these atoms are actually ions, which they have an electric charge and they produce an electric charge in the human body. And that's why they're called electrolytes because of this electric activity inside the body caused by ions. We can measure this in many ways, the electrical activity of these ions or how we get tracings on our EKG ECGs, electrocardiograms, same with EEGs, electroencephalograms. So ions play a role as electrolytes, but also ionic bonds are important, too. Probably the best example of an ionic bond being important in the human body, they do play a big role in the shape of our proteins, and we know that the shape of our proteins determines their functions. All right, so that's ions, that's different types of ions, and that's why they're critical in human anatomy and physiology. I hope this helps. Have a wonderful day. Be blessed.