正象太阳是太阳系的中心天体一样，原子核是原子的核心。

Just as the sun is the central body of the solar system, so the nucleus is the core of the atom...

youdao

正象太阳是太阳系的中心天体一样，原子核是原子的核心。

Just as the sun is the central body of the solar system, so the nucleus is the core of the atom...

youdao