Question

which of the following is not part of daltons atomic theory?
atoms combine in simple, whole - number ratios to form compounds.
most of the atoms mass and all of its positive charge is contained in a small core called the nucleus.
each element is composed of tiny indestructible particles called atoms.
all atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.

Explanation:

Dalton's Atomic Theory states that atoms combine in simple whole - number ratios to form compounds (so the first option is part of the theory). It also says that each element is composed of tiny indestructible particles called atoms (third option is part of the theory) and all atoms of a given element have the same mass and other properties that distinguish them from atoms of other elements (fourth option is part of the theory). The statement “Most of the atom’s mass and all of its positive charge is contained in a small core called the nucleus” is part of Rutherford's nuclear model of the atom, not Dalton's Atomic Theory.

Answer:

B. Most of the atom’s mass and all of its positive charge is contained in a small core called the nucleus.