mixing up endothermic/exothermic processes

[riseNshine]

Hey guys, so I'm a little confused.

I thought that in order to be ionized, you need energy to lose an electron, and this is considered an endothermic process. Similarly, if you want to gain an electron (that is, your electron affinity), you release energy.

However, when I think of it in terms of orbitals; when an electron goes from n=4 to n=3, we say that this process involves a loss of energy, making it exothermic, and to get excited from n=3 to n=4, you need to be excited and gain energy, making it endothermic.... which is contrary to my line of thinking in the above paragraph.

am i missing something? i feel like it's simple, but im confusing myself. thanks.

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[PingPongPro]

I don't really understand your question. I think I do, but can you explain it a little clearer?

I think you are mixing up what is losing/gaining energy in each circumstance. This probably doesn't help, but if you can restate your question, maybe I can be more helpful.

 

[riseNshine]

Sure...

-to be ionized, an atom needs energy so it can lose its electron. (considered endothermic).
however, when an atom loses an electron, going from n=4 to n=3 for instance, we say this is a loss of energy which is inconsistent with the above statement.

 

[PingPongPro]

To be ionized, the atom gains electrons (endothermic). This energy has to come from somewhere. The source is losing energy, so this would be considered exothermic. It is kind of confusing, but you need to consider what is the system and what is the surrounding.

So when an atom is goes from n=4 to n=3, it emits a photon (exothermic), but the surrounding is endothermic since this energy must be put somewhere.

I hope this helps. Just remember an endothermic reaction and exothermic reaction are both occurring. The difference lies with which perspective you look at the reaction. Since energy is being lost at one place, energy must be gained at another.

I hope this helps.

 

[indianjatt]

Ionizing an atom is an endothermic process because you have to input energy in order to eject it in a sense (like the photelectric effect). If an atom gains an electron, then it is an exothermic process.

 

[medicman327]

It sounds as if you're conflating the photoelectric effect with atomic spectra. When you talk about an electron going from an n=4 orbital to an n=3 orbital, the atom isn't losing an electron, it's merely shifting orbitals and a photon is released. That is atomic spectra

However, for ionization to occur, as in the photoelectric effect, energy has to be put in before an electron can be released. When the accepting atom gets the electron it lowers the energy of the atom and energy is released. Remember the electron likes being around the nucleus of an atom, regardless of whether it would like it better with a different atom. Think about a girl in a bad relationship, she might be happier with another guy but she still has to expend some emotional energy to break away from the bad relationship first.

I would probably wouldn't use the words exothermic or endothermic, yet. Try to grasp what is going on first...

 

[tendiw]

I'm glad you helped OP with the best explanation here. You're right that he should go near thinking about endothermic and exothermic questions. It's simply a photon absorption and emission problem.

Good work sir