If you would like to perform your work tasks without interruptions from Google Chat notifications, there is a new feature in Google Calendar, coupled with Focus time, that will allow you to do so.

• Open Google Calendar and click on a timeslot to create a Calendar event.
• Select Focus time from the top of the event.
• Check the Do not disturb box, which will mute all Chat notifications.

For additional details, see Making focus time more productive with new Google Calendar setting.