Question

which of these discoveries contradict components of daltons atomic theory? check all of the boxes that apply.
atoms contain smaller particles: protons, neutrons, and electrons.
atoms of a given element can bond to other atoms only in specific ways.
atoms of a given element can have different numbers of neutrons.
nuclear reactions can change an atom of one element into an atom of another element.
all atoms of a given element have the same number of protons.

Explanation:

Dalton's atomic theory stated that atoms are indivisible. The discovery that atoms contain smaller particles (protons, neutrons, and electrons) contradicts this. Also, Dalton's theory implied all atoms of an element are identical in all aspects. Isotopes (atoms of a given element with different numbers of neutrons) and nuclear reactions changing one element's atom to another (as Dalton thought atoms of one element cannot be changed to another) go against Dalton's ideas. Atoms bonding in specific ways and all atoms of a given element having the same number of protons (atomic number concept which is a refinement, not a contradiction to the essence of Dalton's theory about elements having unique atoms in some sense) do not contradict Dalton's core theory.

Answer:

Atoms contain smaller particles: protons, neutrons, and electrons.
Atoms of a given element can have different numbers of neutrons.
Nuclear reactions can change an atom of one element into an atom of another element.