hello in today's video we're going to be talking about azx notation and ax notation is a way for us to identify the number of protons the number of neutrons and the number of electrons for a specific atom now for your textbooks and many textbooks uh they will only use the letter A the letter Z and the letter X for our class we're going to add one more and that's going to be the letter c and it's written in the upper right hand corner so this is the symbol our ax symbol that we'll be using to to identify the number of protons neutrons and electrons within a given atom uh so let's break this down let's identify what each of these symbols mean the X in ax notation is the atomic symbol that is the one or TW letter symbol that's found on the periodic table each element has a specific and unique uh atomic symbol let's say for carbon it's the letter c for nitrogen it's the letter N for Cal calcium is the letters c and a c a so here we have X that is the atomic symbol it's found on the periodic table in the bottom left hand corner we have Z this is the atomic number atomic number this is equal to the number of protons that are found within that atom so Z is the number of protons within the atom each element on the periodic table has a unique number of protons and that will identify the atom for us so we're always going to be looking at the number of protons to identify the atom so for carbon there are six for nitrogen there are seven for oxygen there are eight uh the number of protons always identifies the atom for us in the upper left hand corner we have the letter A this is the mass number not to be confused with the atomic mass that's found on the periodic table the mass number is not found on the periodic table directly and so the mass number is actually the number of protons plus the number of neutrons so if we know the mass number for a specific element we automatically know the the number of protons because that each element has a unique uh number of protons and we can find that off the periodic table then we can solve for the number of neutrons and the number of neutrons can change for a given element so carbon can have six neutrons seven neutrons or eight neutrons and we're going to have to identify how many are given for a specific is so we have atomic symbol X atomic number Z mass number a now the one that I want to add for our class is C in the upper right hand corner this is the charge and this is going to be uh taking into account that protons have all the positive charge and electrons have all the negative charge so in order to identify what the charge is on a given particle or given atom we're going to take the number of protons and subtract the number of electrons okay so this will tell us the charge so if we think about this if let's say carbon has six protons and six electrons that would give us a zero for the charge and that makes sense each of the protons carries a plus one charge so there are total of plus six each of the electrons carry a negative charge so they're ne6 so when you sum those together you get a total of zero charge on that atom so this this is the breakdown of our ax notation remember X is the atomic symbol Z is the atomic number a is the mass number and C is the charge now we're going to be doing a lot of problems where we have some of this information or most of this information and we are going to be solving for the rest of the information that we do not know so this is our ax notation and that's all I want to say have a good night