Queries :: Populating New Field In Existing Database

I am trying to add a new email field to my existing database of 900 employees. I have imported an excel worksheet of email addresses into a new table that has lastname, firstname, employee#, email. The primary key on the new table is email. The primary key on the employee table is employee#, and there is a new field titled email.

The email field in both tables are text fields. In running an append query, it either adds 900 to 27000 additional fields of email only or it says cannot complete because of key code violations. On the join properties I have clicked on #3 all records from source to only equal fields of destination.