Compounds that have the same molecular formula but different chemical structures are called isomers. Remember isomerism is a property between a pair (or more) of molecules, i.e. a molecule is an isomer of another molecule. A similar relationship is that of brother or sister...
Many Americans are up in arms. But in fact, keeping out desperate souls seeking entry into America has deep roots. On this day 100 years ago, the United States passed the strictest immigration law of its time: the Immigration Act of 1917. The law restricted the immigration of undesirables, including many people from the Middle East and Asia, through increased taxes, tests and outright bans.
Laws passed in 1885 and 1887 were among the first to restrict immigration based on economic concerns. Labor issues remain a major part of the modern immigration debate. From 1900 to 1921, Congress established a quota system, which granted permission to a set number of individuals from each ethnic group to immigrate.