____ and neutrons are found in the nucleus of an atom. Electrons each have a ____ charge. Protons and ____ each both have a mass of ____ atomic mass unit. The mass of an electron is very ____ or ____. ____ are found in shells orbiting the nucleus of an atom. The ____ is the centre of an atom.

The Atom

打印
嵌入

排行榜

视觉风格

选项

切换模板

恢复自动保存：？