HOW IS THE STRUCTURE OF AN ATOM 3-D ?

Structure of atom: The basic units of atom are:

• Electrons
• Protons
• Neutrons

The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons. The electrons of an atom are bound to the nucleus by the electromagnetic force. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it is positively or negatively charged and is known as an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.94% of an atom's mass is concentrated in the nucleus, with protons and neutrons having roughly equal mass. 

Purpose of atom can be understood by taking purpose of sub-atomic particles into consideration.

• Role of electrons: Electrons revolve around the nucleus of an atom just to balance the positive charge created by protons present inside nucleus.
• Role of Protons: Protons are present inside the nucleus to balance the charge of electrons and make atom neutral.
• Role of neutrons: The primary role of the neutrons in the nucleus of an atom is to contribute to the binding energy or nuclear glue that holds the nucleus itself together. Recall that an atomic nucleus is made of protons and neutrons. Protons have a positive charge, and they don 't like each other. In order to overcome the repulsive forces of the protons, neutrons are included in the structure to contribute to the so-called mass deficit. That phenomenon involves the nucleons (the protons and neutrons in a nucleus) losing a bit of mass that is converted into binding energy to hold the nucleus together.

In 3D, these electrons, protons and neutrons are very well explained by 3D-diagrams. In 3D diagram, the electrons are shown to revolve around the nucleus while protons are being showed at the center of the atom.