Why Does an Electron Slow Down Near a Charge?

[Laurie01]

Question: An electron is moving towards a source charge, and slows down. What is the source charge (a proton or an electron)?

I feel like this question is pretty vague (because it says it moves towards the charge (making me think proton), but yet it slows down (making me think electron)) and I'm wondering how you guys would answer it.

 

[nicksauce]

You cannot infer the identity of the source charge from the fact that an electron is moving towards it. It could be moving towards it due to some external agent. You can only infer the identity of the source charge from the fact that it slows down.

 

[Laurie01]

So it would be an electron.

Does an electron ever slow down as it approaches a proton in terms of it slowing down to fall into orbit?