Asked by k.

What theory did Dalton propose about the structure of matter?

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Answered by GPT-5 mini AI
John Dalton (circa 1803) proposed the first modern atomic theory. Its main points were:

- Matter is made of tiny, indivisible particles called atoms.
- All atoms of a given element are identical in mass and properties.
- Atoms of different elements have different masses and properties.
- Compounds are formed when atoms of different elements combine in simple whole-number ratios.
- Chemical reactions are rearrangements of atoms; atoms are not created or destroyed in chemical reactions.

Brief note: later discoveries modified Dalton’s ideas — atoms have internal structure (electrons, protons, neutrons), atoms of the same element can have different masses (isotopes), and nuclear reactions can change atoms — but his theory laid the foundation for modern chemistry.