Determine the number of valence electrons in each element. Which elements do you expect to lose electrons in chemical reactions? Which do you expect to gain electrons? a. Al b. Sn c. Br d. Se

Video transcript

hey everyone in this example for each given element, We need to identify their number of valence electrons and determine whether the element is going to gain or lose electrons. So when we think of gaining or losing electrons, we want to recall the term electron affinity. And we should recall that the lower the number of valence electrons on the atom will correspond to the atom being less likely to gain electrons. We also want to recall how electron affinity appears on our periodic table. And we're just going to imagine the trend for electro negativity because it's the same as electron electron affinity. So it's going to be increasing as we go towards the right and up upward on our periodic tables. So looking at our first example, we have the atoms sodium We should recognize sodium is in group one a on the periodic table. And so we would recall that being in group one a corresponds to having one valence electron. And so because we only have one electron, one valence electron on this sodium atom, that's a low number of valence electrons. And so we would say that therefore we assume that sodium will lose electrons or lose its single electron. Next, we're going to continue to the second part of this question part B where we have iodine, we should recall that iodine is in Group seven A. On the periodic table and therefore has seven valence electrons. And so we would conclude that because this is a high number of ants electrons. iodine is expected to gain electrons. It has a high electron affinity moving down to sulfur. We should recall that sulfur is in group six a. On the periodic table and therefore has six valence electrons. And so we would say that because this is a high number of valence electrons, therefore sulfur is expected to gain electrons because it should have a high electron affinity. And lastly we have calcium recall that calcium is in group two a. On the periodic table. And so that corresponds to having two valence electrons and its outer shell. And so overall this is quite a low number for valence electrons. And so we would say that therefore calcium is expected to lose electrons. And so overall our final answers for this question is this entire boxed in part for parts A through D of this question. So I hope that everything we reviewed was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.