What is the range of keywords per group of ads?
The best rule of thumb is to use no more than 20 keywords per ad group. Sometimes you can get away with using a few more, but exceeding a 20 keyword limit is a sign that your ad copy isn’t matching the keyword being searched as closely as it could.
Don’t add more than 20 keywords per ad group . You want to keep your ad groups tightly themed and the fewer keywords you have the better. Too many keywords leads to low click-through rates and poor quality scores