Question

which of these is not a belief that j. j. thomsons plum pudding model was based on?
a all atoms are neutral.
b an atom has positive and negative charges.
c negative charges balance positive charges.
d positive charges are embedded in a negative sphere.

Explanation:

The plum pudding model by J.J. Thomson proposed that atoms have positive and negative charges (B), negative and positive charges balance (C), and positive charges are embedded in a negative sphere (D, the "plum pudding" idea). The idea that "all atoms are neutral" (A) is not a basis of his model—neutrality comes from charge balance, but the model's core is about charge distribution, not stating all atoms are neutral as a defining belief of the model.

Answer:

A. all atoms are neutral.