which pairing below does not correctly match the scientist with the contribution to the understanding of the atom

A. Proust and the realization that the elements of compounds are found in certain proportions by mass
B. Thomson and the law of definite proportions.
C. Dalton and the initial proposal of the atomic theory of matter
D. Rutherford and the understanding that the atom has a small, dense nucleus with a positive charge

I would look at B as the incorrect one.

To determine which pairing does not correctly match the scientist with the contribution to the understanding of the atom, let's analyze each option:

A. Proust and the realization that the elements of compounds are found in certain proportions by mass: This statement is correct. Joseph Proust contributed to the understanding of chemical reactions by discovering the Law of Definite Proportions, which states that elements combine in fixed ratios by mass to form compounds.

B. Thomson and the law of definite proportions: This statement is incorrect. J.J. Thomson's main contribution to the understanding of the atom was his discovery of the electron and the development of the plum pudding model of the atom.

C. Dalton and the initial proposal of the atomic theory of matter: This statement is correct. John Dalton proposed the atomic theory, which explained that atoms are indivisible and combine to form compounds in fixed ratios.

D. Rutherford and the understanding that the atom has a small, dense nucleus with a positive charge: This statement is correct. Ernest Rutherford conducted the gold foil experiment, which led to the discovery of the atomic nucleus, a small, dense region in the center of the atom with a positive charge.

Therefore, the pairing that does not correctly match the scientist with the contribution to the understanding of the atom is:

B. Thomson and the law of definite proportions.