Why does one process have many different PIDs, besides the list is dynamic?

Question

linux

It was necessary to close the process through console mode (open chrome). I checked the PID of the process with ps aux | grep google-chrome

But I could not kill the process with kill, because it did not find the process by the number received.

I look at the PID of processes through top, and there are many of them that are repeated. The list is constantly changing. In the same chrome, I have only one tab open now, and there are several processes.

Why does one process have many different PIDs, besides the list is dynamic?