Under the county manager plan all of the legislative powers of the county, however conferred or possessed by it, shall be vested in a board of five members to be known as the county board (“the board”). The members of the board shall be elected in the manner hereinafter provided for terms of four years. The board shall elect one of its members as chairman, who shall preside over its meetings. The chairman shall be elected by the board annually and any vacancy in the office shall be filled by the board for the unexpired term. The chairman has the same powers and duties as other members of the board with a vote but no veto and is the official head of the county. With the exception of those officers whose election is provided for by popular vote in Article VII, Section 4 of the Constitution of Virginia, board members shall be the only elective county officials. The board shall be a body corporate and as such has the right to sue and be sued in the same manner as is now provided by law for boards of supervisors.