Question

Any two observations which support the fact that atoms are divisible?
(a)- Discovery of electrons
(b)- Discovery of protons
(c)- Both discoveries of electrons and protons
(d)- None of the above

Answer 1

Dalton said that the atom is the smallest particle in a substance and it is the smallest thing that participates in the reaction and it is indivisible, but later many particles inside the atom were discovered. Three particles were the most important whose charges are one unit positive, one unit negative, and neutral.

Complete answer:
After combining the chemical laws of combination, we could easily study the matter. So, after studying these, Dalton gave many postulates in which the atom is the smallest particle in a substance and it is the smallest thing that participates in the reaction and it is indivisible.
So, later this statement was stated wrong because many small particles were discovered in which three particles are the main, i.e., electrons, protons, and neutrons.
From these three, electrons and protons are given in the question. Electron is a particle having a unit negative charge and it was discovered in 1897 by J.J. Thomson by studying the cathode rays. Proton is a particle having a unit positive charge and it was discovered in 1886 by Goldstein by studying the anode rays.
So, both these discoveries explained that the atom is divisible.

Therefore, the correct answer is an option (c)- Both discoveries of electrons and protons.

Note:
Neutron is the third important particle in the atom which doesn't have any charge as it was discovered by Chadwick in 1932 by bombarding some light elements like beryllium and boron with fast-moving alpha-particles.