Are square roots rational numbers?

Some are, and some aren't.

The square roots of 4, 9, 16, 25, 36, 49, 64, 81, 100, and a lot of other numbers

are rational.

The square roots of 2, 3, 5, 6, 7, 8, 10, 11, 12, and a lot of other numbers

are irrational.

The square roots of 4,9 etc are rational and numbers such as 2,3,5 etc are irrational. some of the square roots are rational and other's aren't.