All elements consists of a very small invisible particles are called atoms.
Atoms of some elements are same and atoms of different elements are different.
#The first model of atom was proposed by JJ Thomson in 1898 called plum pudding model.
According to this model, the positive charge of the atom is uniformly distributed throughout the volume of the atom and the negatively charged electrons are embedded in it, like seeds in a watermelon.
Later, Rutherford worked on it and named this model as Rutherford’s Model of atom in 1911. Rutherford was student of JJ Thomson.