If my mom lived with me for 5 months before she passed away. Can i still claim her as a dependent on my taxes

[DoninGA]

You can claim your mother as a dependent if they meet all the rules for a Qualifying Relative.  If you can claim her, then when entering her personal information you will be asked if the dependent passed away.  You must answer Yes and then the date of passing.

To be a Qualifying Relative -

1. The person cannot be your qualifying child or the qualifying child of any other taxpayer. A child is not the qualifying child of any other taxpayer if the child's parent (or any other person for whom the child is defined as a qualifying child) is not required to file an income tax return or files an income tax return only to get a refund on income tax withheld.
2. The person either (a) must be related to you or (b) must live with you all year as a member of your household.
3. The person's gross income for the year must be less than $5,050 (social security does not count) in 2024
4. You must provide more than half of the person's total support for the year.
5. The person must be a U.S. citizen or a U.S., Canada, or Mexico resident for some part of the year.
6. The person must not file a joint return with their spouse 

[Opus 17]

Yes, if you meet the tests.  For a parent, the relevant tests are 

1. the person had less than $5050 of taxable income for 2024, and

2, you paid more than half their overall support. 

Remember that social security may not be taxable income, but it does count as support they provided themself.  You would need to add up their support costs and determine that you paid more than half.  

The fact that she passed away during the year does not change the tests, she is eligible if she was alive all 365 days or even just 1 day, as long as the other tests are met.