How do I deal with my Alzheimer's mother, who is getting more bitter, hateful and angry?

One more week. Keep saying to yourself "one more week and then she will be in memory care." You are one week away from being able to take some much, much needed respite from your mother. Start planning what you will do for respite.

It is important that you take time away from your mother and heal the wounds that her disease has caused you. Be kind to yourself knowing that she is being looked after by professionals.

Do you feel your work has suffered? Perhaps you can throw yourself into a project at work?

It will take some time to renew your commitment to yourself and your work. If you have a hobby, do it. If you don't, find one. Visit your local library for ideas and books on subjects that interest you.

Coping requires healthy coping skills. I also suggest reading Roz Chast's book "Can't We Talk About Something More Pleasant?"

My mom used to say terrible things to me, threatening to harm me, calling me names and threatening to throw me out of the house. Last year when she fell due to a UTI she told the doctor that we were fighting and I pushed her. That really upset me because I would NEVER do anything like that! I understand though that it was the dementia that made her act that way. She was in a nursing facility and they put her on seraquel because she would have angry outbursts. It has helped. She still gets angry but she will apologize to me now.

If your mother has been diagnosed by a professional trained in the cognitive processes of geriatric patients, it may be well beyond her present capacities to be aware of being purposefully “hateful, angry, and resentful”.
The behaviors that you and your family observe may represent what you interpret as negativity directed toward you, but to allow yourself and your siblings to consider them actual expressions of her feelings is not fair to any of you.
My LO has cursed me, accused me of causing her to have a heart attack, threatened to harm herself because of my care, and other sad things, and since I know the comments are coming from the damage in her brain, I am able to disregard them and stay calm when she reacts as she does.
This actually becomes a necessary source of self discipline when caring for someone with dementia.
It has helped me to avoid situations, when possible, that trigger her. We used to LOVE to go to Church together, but since her placement in the locked memory unit of a very good AL facility, I have found that when the service is over, she expects me to “take her home”. I have chosen to avoid the church service for the time being, and will try again in a month or so, hoping that she will have forgotten her previous responses.
If your mother responded very differently before her sad “decline”, when she was able to manage her responses in a kinder and more positive way, it may help you to remind yourself of how she would have responded in the past, WHEN SHE WAS WELL.
I visit my LO most days, and very rarely am I able to leave the facility without thinking of our past together, when she was a solid companion and confidant, and I could totally trust her wisdom and judgment. Now I can give her former kindness back, by disregarding her sometimes harshness, and remembering that she CAN’T control what she’s saying, and DOESN’T MEAN TO BE UNKIND TO ME.
I wish there were an easy solution. My LO takes a small dose of an antianxiety medication that reduces, but does not omit, her outbursts.
I’m so sorry that this is happening to you. I’ve been part of the family care team of five relatives with dementia, and although I’ve learned from each, it’s never gotten easier. Hopes for peace.