Google got it right on that one, "there is a book on the school table" is okay.
Indeed "on" means that the book is "sobre a mesa" (e ao mesmo tempo em contato).
With "there is a book on" I see that there´s no problem to accept, but "the school table" puzzled you. That happens because in English, like new students like to say "em inglês fala-se de trás pra frente" (referring to the word order with adjectives-nouns).
This way, "mesa da escola" turns into "school table", all mixed togheter in a whole sentence now: "there is a book on the school table".
Licence plate - placa de carro.
Luxury car - carro de luxo.
Beautiful girl - garota bonita.
Computer school - escola de informática.