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Ch.8 - Periodic Properties of the Elements

Chapter 8, Problem 114b

Consider the elements: Na, Mg, Al, Si, P. b. Which element has the smallest atomic radius?

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everyone in this example, we need to identify which of the below element is expected to have the smallest atomic radius. So we should first recall our trend for atomic radius on our periodic table. And we would recall that our atomic radius is decreasing as we go from left to the bottom right of our periodic table. So starting off with our first element potassium, we would recognize that it starts off in group one a. And it's going to be falling across period four. Next we have the atom calcium which we would recognize is in group two A. On our periodic tables. And it's also across period four. Moving on to our next element, we have gallium which you would recognize is in group three a on our periodic table. And also falls across period four. Then we have germanium which we would recognize is in a group for a on the periodic table and also across period four. And lastly we have arsenic which we would recognize as in Group five A on our periodic table and is also falling on our period four on the periodic table. So because all of these elements are all in period four, meaning they're all in the same row. We can't compare them by which element is lowest on our periodic table because that would correspond to the largest atomic radius. But in this case we can go ahead and focus on their group number to determine which adam is the most right most on our periodic table. So more towards the right direction to give us the smallest atomic radius. And what we would say is that because we have our arsenic atom in Group five A, which would be all the way over here on our periodic table. So we would say five days around here, we would go ahead and confirm that therefore arsenic has the smallest atomic radius. And that is due to the fact that Group five A. Is to the right most position of our periodic table. And so the final answer to complete this question is going to be arsenic, which corresponds to choice E in our multiple choice. So I hope that everything we went through is clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.