How can Qin Shi Huang be the first Chinese Emperor if there was a dynasty before him?


Whenever I read or watch something about this, previous dynasties are mentioned. A quick google check shows there''s three, Xia, Shang and Zhou (though I''ve been told that Xia may not have actually existed).
So how can he be the first emperor? Where the previous dynasties not empires? Is this splitting hairs?

每当我读到或看一些关于这方面的东西时,都会提到以前的朝代。 谷歌的快速检查显示有三个朝代存在,夏、商和周(虽然有人告诉我,夏可能并不存在)。