The state is recommending 14 days of quarantine if you're exposed. In a school where just about all the adults can be expected to come into contact with each other over the course of one or two school days, once case would result in just about the entire staff in quarantine.
Nope. "Contact" is defined by the CDC as being within 6 feet for 15 minutes or more. Secondary contacts are not quarantined (reading verbatim from the document sent out by my county's schools). So if a student gets diagnosed, only those students who have been within 6 feet for 15 minutes would be required to quarantine, and anyone who was in "contact" with the quarantined students won't have to do anything. So at most an elementary student could only take out their teacher and some classmates, not the whole school.