(c) Ti and Hf behave as though they possess the same number of valence electrons. Which of the subshells in the electron configuration of Hf behave as valence orbitals? Which behave as core orbitals?

Video transcript

Welcome back everyone. We need to determine the core orbital's and valence orbital's for adam tantalum here. So we should recall on our periodic table that tantalum is located in Group five B of our transition metal D block. And it's located across period six, Which is our 3rd row of our d block. So we're utilizing this position of our adam tantalum to write out its configuration and we're going to use the noble gas shortcut configuration where we would find the noble gas that comes before period six on our periodic table. And we would see that that corresponds to our noble gas being Xenon. So that would begin our configuration moving forward in our configuration. We should recognize that Xenon begins at atomic number 54 tantalum in our sixth period of our D block is at atomic number 73. And so to move forward in our configuration, we need to go through our atomic numbers 57 or sorry, 55 through 70 because recall that tantalum has atomic number 73 meaning that we need to fully fill in our F block on our periodic table, which we should recall begins at the fourth energy level. So our configuration would read four F. And recall that R. F block has a total of seven orbital's which can hold a maximum of 14 electrons that we're going to want to fully fill in. So we have four F 14 continuing continuing on our configuration and then we would move to our third row of our D. Block where we recognize tantalum is located, which we should recall begins at the fifth energy level. So we would have five D and in our D block we would count for a total of three units to represent our three electrons to land owner adam tantalum but we should also recognize that we passed through our sixth period of R. S block. So we would have to fill in those electrons there. So we have six s to to complete our configuration here and again recall that at the sixth period of R. S block. We are also at the fifth energy level of our D block, which is why we have this to complete our configuration of tantalum. So as the prompt states, we want to list our core orbital's and our valence orbital's. So we want to begin with our valence orbital's and we should recall that that is our outermost electron orbital's. So looking at our configuration, we would see that we have the outermost energy level being our 5th and 6th energy level. And so that means that our exponents here, which represent our electrons would fill in would represent our valence electrons, meaning that we can say that five D and six s are our valence orbital's. And sorry, that says orbital's. And because we have those exponents three and two adding them together, we would say we have five valence electrons. Now we only have five valence electrons and these are our valence orbital's for the electrons of our valence orbital's because these orbital's are not fully filled in more specifically, our D orbital was not fully filled in, recall that in our D block we have a total of five orbital's which can hold a maximum of 10 electrons and we've only filled in three here. And so that means that because the rest of our orbital's, which would be our Orbital's from our configuration of Xenon and then our f orbital here, which is fully filled in with its 14 electrons. This would therefore be our core orbital Or core orbital's because we're including the orbital's from Xenon configuration. And so we would identify that there and to figure our total number of electrons in our core orbital's we would recall that Xenon on our periodic table has the atomic number 54. Recall that atomic number represented by the symbol Z corresponds also to our number of electrons, meaning that we also have 54 electrons. And because we know in our f block, we fully filled in the 14 electrons there, we would say we would have 54 electrons plus 14 electrons from our F block equaling a total of 68 core electrons. And so for our final answer, we have determined that our core orbital's include our orbital's that make up our configuration for Xenon as well as our four f orbital. And then for our valence orbital's we've determined that that would be our five D not fully filled in orbital and then R six s higher energy level orbital's, so everything highlighted in yellow represents our final answers. I hope that everything are viewed was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.