Question

Which part of Dalton's original atomic theory must be modified with the discovery of isotopes? *

Compounds are formed when elements enter into chemical reactions

Atoms combine with other atoms in whole number ratios to form compounds

Matter is composed of atoms

All atoms of a given element are identical​

Answer 1

Answer:

Part two of Dalton's theory had to be modified after mass spectrometry experiments demonstrated that atoms of the same element can have different masses because the number of neutrons can vary for different isotopes of the same element.