The mayor or other chief executive officer of the municipal corporation, by whatever name known, shall give notice by posting and publication of any submission of a proposed charter amendment to the voters thereof. For not less than the four weeks immediately preceding the election at which the question is to be submitted a complete and exact copy of the wording of the proposed amendment or amendments shall be posted at the town hall or other main municipal building or in a public place. On the day of the election, a similar copy shall be posted at the place or places for voting. Notice of the election, together with a fair summary of the proposed amendment or amendments, shall be published in a newspaper of general circulation in the municipal corporation, not less than once in each of the four weeks immediately preceding the election.