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Ch.6 - Ionic Compounds: Periodic Trends and Bonding Theory

Chapter 6, Problem 81

Cesium has the smallest ionization energy of all elements (376 kJ/mol), and chlorine has the most negative electron affinity 1-349 kJ/mol2. Will a cesium atom transfer an electron to a chlorine atom to form isolated Cs+1g2 and Cl-1g2 ions? Explain.

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Hey everyone, we're told that the first ionization energy of rubidium is plus 403.0 killed Jules Permal. And the electron affinity of flooring is negative, 328.0 killed Jules. Permal. Is it favorable for an electron to be transferred from a rubidium atom to a flooring atom forming individual rubidium plus one and flooring minus one ions first. Let's go ahead and write out our reaction. So we have the first ionization energy of rubidium. So we have rubidium in its gaseous form and we get rubidium with a plus one charge plus an electron. We were told that our energy was plus 403. joules per mole. Now let's go ahead and look at the electron affinity of flooring. So we have flooring in its gaseous state And we add one electron. So we end up with flooring within -1 charge in its gaseous state. Our energy is going to be negative. 328.0 killer jewels per mole. So our overall reaction comes up to rubidium plus flooring And we end up with rubidium with a plus one charge plus flooring with a -1 charge. Now to calculate the total energy, we end up with plus 75.0 killer jules Permal Since we took our 403.0 kill drills per mole And added that negative 328.0 killed joules per mole. And that's how we ended up with 75.0 killed jules per mole. Now, as we can see right here, our total energy came up to be positive, and because we have an energy that is positive, this means that our reaction is not favorable, since it requires an input of energy to proceed. So the final answer to this question is that the electron transfer is not favorable because the total energy of the process is positive. Now, I hope that made sense and let us know if you have any questions.