Mute all key?

Is there a key to mute everyone? I just want to know because I am afraid of getting banned. I had 3 toxic teams in a row in flex and solo que and I cant take it anymore. I dont want to get banned and sometimes I talk back to them. Im better off muting everyone im not friends with so they dont tilt me. I am not toxic but when other people are it tilts me and sometimes I say something back to them. To me if someone is doing bad as long as they arent building troll then what can you do. Sometimes its just a bad game and you need to move on. Is it ok to mute everyone at the start, or is it refusing to communicate with my team and I can get banned? I feel like all these toxic people are starting to affect my behavior as well