Identify the element represented by each of the following symbols and give the number of protons and neutrons in each: (a) ⁷⁴₃₃X

Video transcript

Hey everyone in this example, we need to identify the symbol number of protons and number of neutrons for the unknown isotope 1 90 X. So let's write out this isotope symbol that were given in the prompt, we have our atomic mass being 1 90. We have our atom X. Which we need to identify and were given the atomic number as 78. So recall that this is our atomic number, recall that that's represented by the simple Z. We also, as I stated, have the atomic mass or mass number. And recall that that is found by taking our number of protons and adding that to our number of neutrons. So now we're going to go ahead and figure out what our symbol is. So what we want to do is find our value for atomic number first. And so if we refer to our periodic tables, we're going to see that our value for Z is equal to or rather it's given to us as 78 and we will see that it is corresponds Z equals 78 corresponds therefore to the atom platinum, which we recall is P. T. On our periodic table. And we would find that in our transition metal D block. So now that we've identified our symbol for X, we can go ahead and actually rewrite our chemical symbols. So now we have a new chemical symbol Being 90 platinum as our isotope here And it still has that atomic number of 78. Now we want to go ahead and figure out as the prompt states number of protons and number of neutrons. So because we recognize that our mass number is 1.90. We're going to first find our number of protons. And we would see that that's equal to our atomic number Z. So this is something that we should recall. And that would tell us that therefore Because we know Z is 78 as given in our symbol in the prompt, we can say therefore we have 78 protons. And this will be the exact number of protons because we don't have a charged symbol, we don't have a charge on our symbol. So this is a neutral atom of platinum. And so now that we know that we have 78 protons, we can now find our number of neutrons by taking our mass number, Which in the prompt again has given us 1 90. Oops, sorry about that. So it's given in the prompt as 1 90. And we're going to subtract that from our 78 protons. This difference gives us our number of neutrons equal to a value of 112 neutrons. So overall we can confirm our final answers. We've identified our number of neutrons here boxed in. We've identified our number of protons equal to our atomic number and we've identified our symbol here with our adam, platinum filled in. So everything boxed in blue represents our final answers for this example. If you have any questions, please leave them down below and I will see everyone in the next practice video.