Question

The atom is indivisible was proposed by:
A. Rutherford
B. Dalton
C. Bohr
D. Einstein

Answer 1

Hint: Democritus developed the idea of atoms. He pounded up materials in his pestle and mortar and reduced them to smaller and smaller parts which he called atoms. Similarly several Greek philosophers developed the concept of atomos, an indivisible building block of matter in the fifth century BCE.

Complete step by step solution:
Democritus explained that the different types of these particles were responsible for its various forms of matter. But his ideas were neglected at that time.
The idea of indivisible particles was later explained by several scientists and philosophers including Galileo, Newton, Boyle, Lavoisier and Dalton.
But John Dalton is credited to introduce atoms as an indivisible particle. He was an English chemist, meteorologist and physicist. He developed modern atomic theory. His theory was different since it had the weight of careful chemical measurements behind it. It was not just a physical statement that there are atoms because there must be atoms. His postulates in atomic theory were used for explaining earlier observations of the behavior of matter.
So an atom is indivisible as proposed by Dalton.

Hence, the correct option is B.

Note: His postulates are given below:
Matter is composed of very tiny or microscopic particles called atoms.
Atom is an indivisible particle.
Atoms can neither be created nor be destroyed.
Atoms of an element are identical in size, shape, mass and in other properties.
Atoms of different elements are different in their properties.
Atoms combine with each other in small whole numbers.
All chemical reactions are due to the combination or separation of atoms.