Notice of the election of any officer of the city shall be given him by the clerk, in writing, within seven (7) days after the canvass of the vote by which he was elected. If within ten (10) days from the date of notice, such officer shall not take, subscribe, and file with the clerk his oath of office, such neglect shall be deemed a refusal to serve and the office shall thereupon be deemed vacant, unless the council shall, for good cause, extend the time in which such officer may qualify as above set forth.