Depends on your story, intent, and your style actually.
1k words are the usual length of 'phone' novels, with reason being, people 'on the go' would always burn some of their idle time (i.e. riding in trains) reading something. Inkitt and Tapas encourage this word count.
Most agree that 1.5k to 2k is the tolerable length for chapters in online publishing.
I use 2k to 3k in my non-fantasy/low fantasy stories, while 4k to 4.5k is my main chapter length for my high fantasy work. My reason is, my novel is meant to read while relaxing, so I do it long. (Not to mention, I do proper build ups before climax, so it gets quite wordy.)
A colleague once told me that anything that reaches 5k and up is tedious to read and intimidates readers, though I did write 6k-6.7k chapters and my audience is fine with it.
Oh and yeah, if you want to end a chapter, better end it with cliffhangers (especially of you're in the middle of your manuscript). As for the end chapters, it depends on you whether to wrap it up or end with a cliffhanger. If you intend those last parts to resolve the characters' problems, wrap it up. If you intend to continue on (applicable if you do your novel by volume/arc), answer some issues, and end with a cliffhanger.
If you're having difficulty of keeping track of your story, you can always do a plot on what's going on. Better yet, backread on your previous chapters, but plotting is much efficient than having to go through the entirety of your work.