What evidence from j. j. thomson's experiments with the cathode ray led to the plum pudding model of the atom? the beam was attracted to a positive charge and repelled by a negative charge, showing that atoms contain small, negatively charged particles. the beam was attracted to a negative charge and repelled by a positive charge, showing that atoms contain small, positively charged particles. the beam was positively charged and had significant mass, showing that atoms have a positive, dense nucleus. the beam was neutral and had significant mass, showing that atoms contain neutral particles in the nucleus.

A.The beam was attracted to a positive charge and repelled by a negative charge showing that atoms contain small negatively charged particles.

Explanation:

We know that J.J Thomson discovered a  particle which is called electron.

J.J Thomson said that an atom is like water melon structure  in which  electron embedded in it.

J.J Thomson's experiment :

He used  cathode ray tube in his experiment which is vacuum sealed tube with a cathode and anode  at one end that creates a beam of electrons travelling towards the other end of tube.

Cathode rays are negatively charged subatomic particles  that is electrons.

Rays were allowed to pass between the two oppositely charged plates.

He observed  that the beam of electron were attracted towards a  positive  charges plate  and repelled by a negative charged plate .

He concluded that atom contains small negatively charged particles known as electrons.

Hence, option A is true.

A.The beam was attracted to a positive charge and repelled by a negative charge showing that atoms contain small negatively charged particles.

answer; i believe that the correct answer is (a) potassium(k)