In this video you're going to learn everything you need to know about atomic structures and chemical symbols. Alright let's do this [Music Playing] Hello Hello Melissa Maribel here and I help students like you understand what you just learned in class so you stress less and you graduate faster. Let's talk about atoms, my friend John Dalton over here came up with the theory that everything is composed of atoms. Random Man: Everything, even this? Melissa Maribel: Let's see, let's see, hmm.. yeah yeah Those are atoms alright, mm.. hmm.. mm.. hmm.. Random Man: What about this? Melissa Maribel: Huh let me see, oh gosh no! Yes, yep those are atoms, those were atoms. mm.. hmm.. Random Man: Even these two? Melissa Maribel: Literally Adams Okay Okay but what makes up an atom? What makes up an atom are three different types of particles protons, neutrons and electrons protons are positively charged, neutrons have no charge or are known as neutral electrons are negatively charged. Let's look at the set up for a chemical symbol the X represents the chemical symbol or the element. A is the mass number Z is the atomic number. For example our potassium or K has a mass number of 39 an atomic number of 19. On the periodic table that 19 or atomic number is on top your atomic mass is on the bottom. Let's talk about the difference between an atomic mass and a mass number. A mass number is our protons plus our neutrons versus the atomic mass is the average of all the different types of isotopes of that element. We will discuss isotopes in a separate video in a neutral compound like potassium just meaning there is no charge your atomic number protons and the electrons are all equal and we see that each one of those is 19. To figure out how many neutrons you have take the atomic mass and subtract that by your protons. Subtracting these two numbers will give you 20 neutrons. Let's talk about ions ions are elements with a charge. Phosphorous has a charge of negative 3 let's figure out our atomic number and how many protons there are. Looking at your periodic table let's figure out where phosphorous is then the atomic number will be on top your atomic number is equal to the same amount of protons so our atomic number and protons will both be 15 if we're trying to figure out how many neutrons you take your mass number or atomic mass which will round to 31 and subtract it from the total amount of protons that then gives you 16 neutrons to figure out your electrons take your proton count and subtract it from the total charge our charge was a negative 3 these two will then multiply becoming a positive so we'll have 15 plus 3 giving us 18 electrons what you could have also seen was since this is a negative 3 charge this is gonna add to the amount of electrons because electrons are negatively charged so they're becoming more negative. Let's look at our next example with an ion with a positive charge. Phosphorus now has a 3 plus charge we're still going to figure out our atomic number, atomic mass, protons, neutrons and electrons, however our atomic number and proton count will not change neither will our atomic mass we'll also round it to 31 and our neutrons will still be the exact same our electrons are the only thing that changes so we'll take our protons and subtract it from our total charge of 3 and that will give us 12 once again our charge is a positive 3 so this is actually going to subtract from our electrons since electrons are negatively charged now what if you're given the amount of protons, neutrons and electrons and you're asked to figure out is it a neutral element or is it an ion. Determine the element or ion that has 26 protons, 30 neutrons and 29 electrons. Here's a trick on figuring out if it's a neutral element or if it's a charged element which is an ion if your protons and electrons are equal to each other that means it is neutral, if your protons and electrons are not equal to each other that means it is an ion in this case our protons and electrons are not equal to each other that means it will be an ion. First off our atomic number is the same amount of protons so we know that it is 26. Looking at your periodic table let's look for the atomic number of 26 as you can see it is Fe also known as iron. If you are asked to figure out the mass number you would add your protons plus your neutrons that would then give you 26 plus 30 which is 56 to figure out your charge take the atomic number or proton count and subtract that by your total amount of electrons 26 minus 29 gives us a negative 3 charge we have iron with a negative 3 charge this is our final ion. Get ready for some practice problems hit it Johnny [Music Playing] I hope you got everything right as always I've linked up practice problems with step-by-step answers in the description box below let me know what you're struggling with if you have a homework problem that you don't quite understand leave a comment and I'll answer it and I'll see you next time. Alright let's do this. [Laughs] Well, that was it, no more takes What's going on in there? It's a popping! Okay I'm done