The minimum number of representatives that a state can have is one. This is clearly stated in Article 1, Section 2 of the United States Constitution.
The number of representatives is allocated according to the proportion of the state's population. Thus larger states have more representatives than smaller ones. The United States House of Representatives has a fixed number of 435 representatives. The number of representatives per state is reapportioned every 10 years after a population census has been performed for each state.
Each state representative, who holds his position for two years, has to be at least 25 years old with 7 of those years spent as a United States citizen. He should also be resident in the state, if not the district, that he represents during the time of election.