Question

1. j. j. thomsons experiments provided evidence that an atom

contains negatively charged particles
has a positive charge
has a negative charge
is the smallest particle of matter

Explanation:

J. J. Thomson's cathode - ray tube experiments led to the discovery of electrons. Electrons are negatively charged particles. Atoms are neutral overall (protons + neutrons in nucleus and electrons around), so Thomson's experiments showed that atoms contain negatively charged particles (electrons). Atoms themselves are not negatively or positively charged (as a whole, they are neutral in most cases), and atoms are not the smallest particles (as they are made up of sub - atomic particles like electrons, protons, and neutrons).

Answer:

contains negatively charged particles