The diagram that follows represents a molecular view of a process occurring at an electrode in a voltaic cell.

(c) Why are the atoms in the electrode represented by larger spheres than those in the solution? [Section 20.3]

Video transcript

Welcome back everyone. We're told that the molecular view of the process taking place at the an ode in a voltaic cell is shown in the diagram below. Why are the spheres used to depict the atoms in the anodes larger than those in the solution? So looking at our diagram given we can see that we have these solid spheres packed tightly amongst one another and we want to recall that this is going to represent a solid because we would recognize that solids are made up of closely packed atoms. So let's label this as our solid metal. Where if this is a voltaic cell or rather the node of a voltaic cell that contains all of these atoms here. We can assume that each of these atoms make up our solid an ode battery here. And so what the image is showing is some of these atoms leaving this solid metal. And what we would assume is that they're going to be going in solution of our voltaic cell. And recall that in our voltaic cell, our solutions contain our ions. Recall that our ions are going to be specifically cat ions which have a positive charge. We recall and these Catalans form because our atoms in this case, this atom that left, I will say the atom loses electrons, which is why we have cat ions that form in our solution. And we should recognize that according to the prompt, we're told that this solid metal is are an ode in our voltaic cell and recall that are an ode occurs as our oxidation reaction. Recall that in an oxidation electrons are released. So it makes sense that these atoms are being oxidized basically and being released or releasing rather electrons to form cat ions in our solutions here. So let's clarify this and say that our oxidized atom, sorry, oxidized neutral adam loses an electron to form the cat ions that we have in our solution. Now, when this loss of our electron occurs, this relates to the effective nuclear charge of the remaining electrons in that atom to increase. So we'll say careening electrons will increase. And with this increase in effective nuclear charge, we have a stronger electrostatic force of our electrons to the nucleus of the atom. And if this effective nuclear charge has increased for this oxidized once neutral atom which is now a ion now a cat eye on we will therefore have a decrease in our atomic radius of our cat. I own where we would recognize that the radius of our neutral atom is larger and that is why, according to our diagram, these spheres depicting our neutral atoms and sorry, this would not be a neutral atom. This would be an oxidized atom going into our solution. But in our solid tightly packed an ode metal here we have these larger spheres which represent our atoms that are much larger than our atoms that have become ions in solution. And that again is because these neutral atoms that make up our an old battery have a larger atomic radius and lower effective nuclear charge since they haven't lost any electrons yet. So the only statement to complete this example, as our final answer is going to be Choice C, which states that the spheres used to depict the atoms in the anodes are larger than those in the solution. Because the atoms and the anodes lose a valence electron form Catalans with smaller, ready and move into the solution. So C is our final answer. I hope everything I went through is clear. If you have any questions, please leave them down below and I'll see everyone in the next practice video.