The Size of Atom
Atom is one of smallest discovered particles of any matter or chemical substance.
Atoms consist of neutrons, protons, and electrons, which form a certain unity and become building bricks of every chemical matter.
The size of atom depends on the very type of atom, because there is different number of electrons, neutrons, and protons in each atom.
Since atoms do not have clearly specified outer boundaries, their size is determined by the distance between the nuclei of adjacent atoms, which form a chemical bond (covalent radius) or the distance to the farthest of the stable orbits of the electrons in the electron shell of an atom (atomic radius).
Therefore, the size of atom can be approximately estimated by referring to the atomic radius, which is equal to 0.5 of the distance between the adjacent atoms.
Thus, atom is a really very small particle, with its diameter being somewhere between 1 × 10-10 m and 5 × 10-10 m.
In order to imagine the size of the atom, one can think about the fact that a 3-feet chain of atoms will consist of about 6 billion atoms.