In this video, we are going to talk about ions. So previously, we discussed atoms, and atoms can carry a charge by varying the number of electrons they contain. And this is a very common occurrence and we're gonna need a special name for this. So an atom with unequal. Number of protons and electrons is called. An ion. And there are two main types of ions that we're gonna look at. The first is a cation, and a cation is a positive ion. That means that the number of protons is gonna be greater than the number of electrons. And we also have anions. And in an anion, we have a negative ion, which means the number of electrons is greater than the number of protons. So we can look at it some examples of various ions that we might see. So if we have sodium and we have sodium 23 which has an atomic number 11, we can look at the number of protons for this atom is equal to 11, the number of neutrons is gonna be 23 minus 11, or 12, and the number of electrons is gonna be equal to 11. This is because this is a sodium atom where there is not a charge. But But, if we look at sodium plus ion, where we indicate that we have a plus 1 charge, which means that the number of protons are gonna be greater than the number of electrons. If we look at all the subatomic particles for this particular In this case, cation. The number of protons are still gonna be equal to 11. The number of neutrons are gonna be 23 minus 11 or 12. But the number of electrons in this case are different, because we have a +1 charge. This indicates we have one more proton than we do electron, so the number of electrons for this particular cation is going to be 10, which agrees with the statement that we made for a cation. The number of protons are greater than the number of electrons. Now let's look at one more example. If we have a nitrogen 15 atom we have 7 protons, 8 neutrons. And seven electrons. Again, this is an atom, the number of protons and electrons are gonna be equal and are gonna be the same. If on the other hand we look at a nitrogen 3- anion, we're gonna have a varying number of electrons compared to a nitrogen atom. Atom so the number of protons for nitrogen is always going to be seven which is its atomic number. The number of neutrons are gonna be 15 minus seven in this case or eight and the number of electrons for this nitrogen three minus anion has to be three more than the number of protons. So the number of electrons here are gonna be 10. Okay, so in this case, we have a sodium cation. And a nitrogen anion. And as we go through this course, we're gonna look at the charges of each of these cations and anions and figure out if there's a way that we could potentially predict what those charges will be. But for now we need a convention to make sure that we know how to look at these. And we need to come up with the vocabulary of how to communicate with a chemist. So in the next video we're then gonna look at something called isotopes when we vary the number of neutrons.