What is one idea Dalton taught about atoms?

One key idea that John Dalton taught about atoms is that they are indivisible and fundamental building blocks of matter. He proposed that each element consists of unique atoms that differ in mass and properties, and that chemical reactions involve the rearrangement of these atoms. Dalton's atomic theory laid the groundwork for modern chemistry by introducing the concept that compounds are formed when atoms of different elements combine in fixed ratiOS.