 Okay, let's do this next problem in lecture notes a little more challenging than the last one It says silver has a total of two isotopes one isotope contains 60 neutron Neutrons and has a percent abundance of fifty one point eight three nine percent the other contains 62 neutral so We'll say isotope one the number of neutrons It contains so we'll just say silver one Silver two I'm always at 60 and 62 and then the percent abundance Okay, so since you have that information what are the mass numbers and symbols of each of these isotopes So the mass numbers of each of these I mean you need to get your calculator now to do this problem probably do it in your head The first thing you have to remember is well, it didn't give you the Elemental symbol for silver so you got to remember that silver is a G. It's one of those weird ones The mass number so if you find a G on the periodic table So look more on the periodic table and when you do you'll see that it's numbers 47 So that's the number of protons it has So remember to be a silver atom you have to have 47 protons So that one's got a 47 and that one's got So the mass number capital A Sometimes is used for mass number is going to be 60 plus 47. I guess you don't need your calculator for them 107 Dalton's or whatever and The bottom one silver to the second isomer of silver or isotope of silver. It's gonna be 62 plus 47, which is 109 don't so that's the mass number of those two So then it wants you to write the elemental symbol for them. So you can now so the first one is going to be a G remember subscript is the Atomic number which is the same as the number of protons 47 and the superscript is the 107 so that's the first silver and then the Atomic symbol for the second one the second Isotope is going to be 109 at the top there And 47 at the bottom Okay, and then it says the second question I believe it said was what was the Percent abundance of the other isotope. So this is what we're looking for So we know it would be 100 point percent Okay, so if there's only these two You just take a hundred and subtract it or subtract 51 point eight thirty nine from it and You get 40 so that's the percent abundance of Silver one on that that answers that question