(a) If the core electrons were totally effective at screening the valence electrons and the valence electrons provided no screening for each other, what would be the effective nuclear charge acting on the 3s and 3p valence electrons in P?

Video transcript

Hey everyone in this example, we need to determine the effective nuclear charge of the three S. And three P valence electrons in sulfur, assuming that only core electrons contribute to the screening constant. So what we should recall is to calculate our effective nuclear charge. We can take our Z. Value or our value for atomic number of our atom and we can subtract this from our number of core electrons. So because this prompt mentioned sulfur, we want to focus on sulfur. Where in the periodic table we would find it in group six A. Corresponding to the atomic number 16. So we would say that Z is equal to 16 for sulfur. And we can write out its configuration the shorthand way beginning with the noble gas neon in brackets and understand that we would go through the three S to sub level as well as the three P four sub level because we would count for four units to land on our adam sulfur. And that's why we fill in four electrons in our P. Sublevel. So what we should recognize is we need to determine because we already know our atomic number of sulfur. We needed to now determine our number of core electrons in sulfur. And we should recall the fact that for neutral atoms only our number of electrons is going to equal our atomic number as well as equal our number of protons. Now, what we're going to do is recognize that because we have the atomic number or Z value of for sulfur, We would therefore say that we have 16 electrons. And because we also recall that sulfur is located in Group six A. Of our periodic table, we would recall that the group number corresponds to valence electrons. So we would have six valence or outer electrons for sulfur. And so to get the core electrons, we're going to Find the core electrons of sulfur by taking our 16 electrons total and subtracting them from our six valence electrons. And this difference gives us a value of 10 electrons for our core electrons. So to calculate our effective nuclear charge of sulfur, We would therefore say that that's going to equal the atomic number of Sulfur, -10 core electrons. And this is going to give us a value of six for our effective nuclear charge of sulfur. And this would include the effective nuclear charge of our three S and three P valence electrons in sulfur. So six is our final answer. 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