What is the Dalton atomic model?
Dalton assumed that matter is made of indestructible particles called atoms. Atoms of the same substance are similar while that of different substances are different.
As he assumed atoms to be indivisible, he didn't know about the existence of elementary particles (Science at that time didn't discover elementary particles and knew nothing about internal structure of atoms). According to his theory, atoms are indestructible and indivisible and don't have an internal structure.