Whenever a united city is formed by a compliance with Section 7-2-1 of municipal government with alderpersons chosen from wards or districts, the united city shall be and the decision is in favor of a managerial form governed, after the first election held in compliance with Section 7-2-7, by a council composed of a mayor and a board of alderpersons selected by the electors of the united city as provided by the provisions of this Code relating to the election of city officers, except all elections in a united city are controlled by the City Election Law as provided in Section 7-2-6, and by a municipal manager appointed by the council as provided in Article 5.