There are only two senators per state and they are elected for 4 year terms. Representative vary from state to state based on population and local districts and they server 2 year terms. The Senate is the higher branch of Congress while the House is seen as the closet representation of the people. We adopted this system from the British where the upper house was made of wealthy land owners or kin to royalty where as the lower house (Commons) is closer to the people just our House of Representatives.