Uranium-235 decays through a complex series of steps, ultimately ending up as lead-207. Here's a simplified breakdown of the process:

1. Alpha Decay: Uranium-235 undergoes alpha decay, emitting an alpha particle (two protons and two neutrons) and transforming into thorium-231.

2. Beta Decay: Thorium-231 then undergoes beta decay, emitting a beta particle (an electron) and transforming into protactinium-231.

3. Alpha Decay: Protactinium-231 also undergoes alpha decay, transforming into actinium-227.

4. Beta Decay: Actinium-227 undergoes beta decay, transforming into thorium-227.

5. Alpha Decay: Thorium-227 undergoes alpha decay, transforming into radium-223.

6. Alpha Decay: Radium-223 undergoes alpha decay, transforming into radon-219.

7. Alpha Decay: Radon-219 undergoes alpha decay, transforming into polonium-215.

8. Alpha Decay: Polonium-215 undergoes alpha decay, transforming into lead-211.

9. Beta Decay: Lead-211 undergoes beta decay, transforming into bismuth-211.

10. Alpha Decay: Bismuth-211 undergoes alpha decay, transforming into thallium-207.

11. Beta Decay: Thallium-207 undergoes beta decay, finally transforming into lead-207.

This process is known as a decay chain, and it involves multiple steps of alpha and beta decay. It's important to note that this is a simplified representation, and the actual decay chain is more complex, involving various isotopes and their decay products.