Our government is comprised of 3 distinct branches: Executive, Judicial and Legislative...
1. The Legislative branch is comprised of both the House of Representatives and the Senate. Commonly referred to individually as "The House" and "The Senate", a member of the House is known as a "Representative", while a member of the Senate is known as a "Senator". Sometimes you'll hear people refer to both the House and the Senate collectively as "Congress". Additionally, you might hear the generic title of "Congressman or Congresswoman" used to represent any member of "Congress". While it's acceptable to refer to any member as "Congressman or Congresswoman", the term "Senator" is reserved exclusively for the members of the Senate. So, we've got The House & The Senate comprising Congress; And Representatives and Senators who are technically all Congressmen and Congresswomen, but only the members the Senate are Senators, while the members of the House are Representatives.
2. The Senate is comprised of 2 people from each state for total of 100 Senators. Each Senator is elected for a 6-year term. And every 6 years, approximately 1/3 of the Senators are up for re-election. In order to serve as a Senator, candidates must be at least 30 years of age, a citizen of the United States for the past nine years prior to the election year, and a resident of the State they'll represent at the time of election. Arizona has 2 Senators, both of whom are Republican, and you can find them here: Arizona's Senators. One of our senators, Jeff Flake, is up for re-election in 2018. He was last elected in 2012.
3. The House is comprised of 441 Representatives, 435 of whom are voting members, and 6 of whom are non-voting members representing Washington D.C., The U.S. Virgin Islands, America Samoa, Guam, the Northern Marianas Islands, and Puerto Rico. The total of 435 voting representatives is based on a different number of Representatives from each state based on each state's population. In order to serve as a Representative, candidates must be at least 25 years of age, a citizen of the United States for the past seven years prior to the election year, and a resident of the State they'll represent at the time of election. Arizona has 9 Representatives (5 Republicans, 4 Democrats) each of whom represent one of Arizona's nine congressional districts. You can find the list of Arizona's Representatives via this link: Arizona's Representatives. All 9 of our Congressional Districts will be voting for their respective Representatives in August and November of 2018.