Do you think it is common for chemists to get 100% yields for chemical reactions? why or why not?

No.

In every reaction, 100% yields are only theoretical; in reality, many factors can cause certain amounts of a product not to be produced. For example, if slight impurities are present in the reaction, some of the reactants might react with the impurity (a tiny amount of another substance), technically reducing the yield to below 100%.