Is it possible for a Jewish person to become an atheist?

Answer 1

Yes; Jews are people just like anyone else. People can make decisions to become atheists. The Torah teaches us to keep its laws (see for example Deuteronomy ch.4 and ch.5), but tells us that God has given us free-will (Deuteronomy 30:15-20) if we decide to disobey.

It goes back to the idea that Jews are ethno-religious as opposed to religious (like Christians or Muslims). Therefore, in the sense that Judaism is a cultural inheritance, a person can disdain the religion (becoming atheist) and still continue to be ethnically Jewish. Similarly a non-ethnic person can convert to become a Jew (in the religious sense).