Atom (The atom structure)

An atom is composed of a positively-charged nucleus orbited by one or more negatively-charged
particles called electrons.The neutrons are electrically neutral, and the protons are electrically
positive. Together the neutrons and protons give the nucleus its mass.The particles that orbit the nucleus are electrons. Each electron is negatively charged, and the charge of one electron is equal in magnitude (but opposite in sign) to the charge of one proton. Each electron is negatively charged, and the charge of one
electron is equal in magnitude (but opposite in sign) to the charge of one proton. 

 An atom is an extremely small electrically-neutral particle. An atom is composed of a positively-charged nucleus orbited by one or more negatively-charged
particles called electrons.
The diameter of the atom is determined by the range of the electrons in their travels around the
nucleus and is approximately 10 ^-8 cm.  The diameter of the nucleus is roughly 10,000 times smaller, approximately 10^-13 to 10^-12 cm.  Because the nucleus is composed of neutrons and
protons that are about 1835 times heavier than an electron, the nucleus contains practically all
the mass of the atom, but constitutes a very small fraction of the volume.  Although electrons
are individually very small, the space in which they orbit the nucleus constitutes the largest part
of the atomic volume.