Chemistry deals with matters and their transformations. Matters are of two types one is pure and another is impure.

Pure matters contain only one kind of particle but impure matters contain more than one kind of particle.

Elements are made by tiny particles called atoms, the particular elements contain only one kind of atoms hence elements are pure substances.

Consider a wall it contain bricks so bricks are building material of wall. We make wall from regular arrangements of bricks. So we can say that bricks are small particle of wall. This is very different things how we made the atoms.

Similarly atoms are building block of an elements. atoms are bricks and element is wall.

Atoms are spherical in shape like ball, it has three dimensional structure, in the Centre of atom there is tiny dense nucleus. electrons revolve around the nucleus in 3d spaces. This space we can call electron cloud.

The nucleus contains positively charged protons and uncharged neutrons, thus nucleus is positively charged. In other hand electrons are negatively charged. The number off positively charged protons and negatively charged electrons are equal hence atoms are neutral.