The two most common isotopes of uranium are 235U and 238U. (b) Using the periodic table in the frontinside cover, write the electron configuration for a U atom.

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welcome back everyone. We're told that naturally occurring neodymium is composed of five staple isotopes. So we have neodymium 1 40 to 1 43 1 45 and 1 and 1 48. We need to write the electron configuration for neodymium. So we're actually going to disregard our isotopes given. And that is because we should recall that isotopes differ by number of neutrons which make up their mass number. Because we recall that mass number, which is listed in our isotope names given here is calculated by taking our neutrons added to the protons of our atom. And so because we recognize that for electron configuration, we're just worried about our electrons. We don't need to worry about the given isotopes from the prompt. So we're just going to consider a neutral atom of neodymium. So that's N. And then lower case D on our periodic tables, which we see corresponds to atomic number equal to 60 on our periodic table. Recall that atomic number is represented by the symbol Z. And so that would tell us that therefore we have 60 protons. And because this is a neutral atom, we have therefore also 60 electrons And we are going to distribute these 60 electrons into our atomic orbital's to make up our configuration of our neodymium. So before we do so we want to recall our orbital's that can make up our configuration beginning with the lowest and smallest energy orbital, which is our s orbital recall that. That has a total of one orbital which can hold a maximum of two electrons. So we can say max of two electrons moving on, we have our p orbital's which we should recall has a total of three orbital's that can hold a maximum of six electrons moving on up in energy we have our D orbital's Would you recall consists of a total of five orbital's which can hold a maximum of electrons and then moving on up in energy. We have our f orbital's Which we recall has a total of seven orbital's that can hold a maximum of 14 electrons. So going back to our neodymium neutral atom, we should recognize that it is located in our Land tonight series of our periodic table. Sorry, that's Land Tonight series which is located in our f block of our periodic table which we should recall begins at the fourth energy level. And that means that our configuration should go all the way up to our four F orbital. And so to begin our configuration, we would say that we need to fully fill up our orbital's all the way up to r four F block. So we have beginning our configuration our one s orbital which we should recall. We fill in two electrons moving on up, we have our two s orbital which we should recall also can only hold a maximum of two electrons moving through our periodic table. We then go to the two p orbital's where we have a total of six electrons that we fill in. Then next we would go to R three S orbital where we should recall. We fill in a total of two electrons. Moving on up an energy we go through our three p molecular orbital where we recall, we can hold a maximum of six electrons. Then moving forward, we have our four s two molecular orbital holding its maximum of two electrons. Then we finally hit our D block which we should recall on the fourth period of our periodic table begins at the third energy level, meaning we would have three D. Because we need to fully fill this up. We would fill in in with a total of 10 electrons moving forward. In our configuration we have our four P block which we recall hold a maximum of six electrons moving forward in our configuration, we get to the fifth energy level of Rs block, holding a maximum of its two electrons moving forward in our configuration. We then get to the fourth energy level of our D block. Which again we want to fully fill into its maximum of 10 electrons. And then we get to and I'll just make some more room for our configuration here. We then get to the fifth energy level of our P block which we recall holds a maximum of six electrons moving up in energy, we have our six energy level of R. S orbital which we recall only hold a maximum of two electrons. And as you can see on our periodic tables when we get to six S two, that leads us to our atom on our periodic tables being barium, which is at atomic number 56. But as we stated, we recognize that Naomi is atomic number 60 meaning that we move on to our F. Block of our periodic table, which we recall begins at the fourth energy level. So we have four F. And we count for a total of four units to land on our atom for neodymium. And that would mean that would correspond to only filling four electrons in our f block to lead us to our atom being neodymium 60. And so for our final answer, that would be our entire configuration that we've outlined here in yellow. So I hope that everything I explained was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.

The two most common isotopes of uranium are 235U and 238U. (b) Using the periodic table in the frontinside cover, write the electron configuration for a U atom.

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Key Concepts

Electron Configuration

Periodic Table

Uranium Isotopes