How to mute notifications in Google Hangouts
You may be on a video call or need some time to focus and you'd prefer classic Hangouts not to ping each time someone sends a message.
How to mute notifications in Hangouts:
In Gmail, go to the chat gadget down the left-hand side. If you don't see the chat gadget you may have it hidden, click the speech bubble icon at the bottom of the left-hand side column to reveal.
Click the drop-down arrow next to your name.
Next, select how long you want notifications to get muted for from the "Mute notification for..." box.
You have now muted notifications.
How to mute notifications for specific chats:
In Gmail, open the conversation you would like to mute.
Click the settings cog in the top right of the chat window.
Remove the “tick” from the notification box.
This chat will no longer ping or popup when new messages are received.
The chat will appear bold in your messages window when new messages have been received.