What are Atoms Made (Composed of) – Properties and History of the Atom

At the end of the article, you will be able to describe –What are Atoms Made (Composed of) – Properties of an atom and History of the Atom. Let’s start discussing it. A matter is any substance that has mass and occupies space. All the objects around you, this book, your pen or pencil and natural things, such as rocks, water, and plants are the subject of the universe. A matter is made up of atoms.

Atoms are Composed of

The question has asked multiple times that atoms are composed of what? Here is the Answer-.  Atoms are composed of electron, proton, neutron and various smaller particles that lies within the nucleus. The smallest indivisible particle of matter is an atom. The various scientist gave the theory about the complex structure of an atom.

  • The charge magnitude of Electron and Proton are same.
  • Neutron has no charge.
  • An electron has a negative charge.
  • Proton has a positive charge.
  • overall nucleus has a positive charge.
  • The whole atom is electrically neutral.

Atoms made of several small particles. Three important particles are

  • Electron
  • Proton and
  • Neutron

These particles are main constituents of the atom we call as fundamental particles. The electrons present around the atom are attracted to the protons. These protons are present in an atomic nucleus. The force with which these electrons are attracted is an electromagnetic force. The protons and neutrons also attract each other in the nucleus. But this force is called as the nuclear force.

Properties of an Atom

  • Dalton, in 1808, proposed that atoms are very very small, inseparable particles.
  • Atoms are tasteless and colourless.
  • An atom is electrically neutral.
  • The number of protons and neutrons together decide mass of atom.
  • The number of atoms before and after the reaction remain same.
  • Atom is the smallest particle of an element that participates in the chemical reaction.
  • When the group of atoms gets together may be same or different types we call as a molecule.
  • The size atom varies between .3 Å(1angstrom=1010 m) to 3 Å.
  • Atom is the smallest particle of an element that retains all its properties and enters into a chemical reaction.

History of the Atom

The concept of atomic structure was given by the three scientists. Out of which Neil Bohr successfully explained the atomic structure.  A comparison between the different models proposed by the three scientist JJ Thomson, Rutherford and Neil Bohr is given below:

J J Thomson Atomic TheoryErnest Rutherford Atomic TheoryNeils Bohr Atomic Theory
An atom consists of a ball. positive charge(+) and electrons(-) are embedded like a seed. The number to the total positive charge equals to the negative charge due to which atom has no charge.It means atoms are electrically neutralAn atom consists of the positively charged nucleus at the center. Electrons revolve around the circular path with a very high speed. There exists an electrostatic force between the proton and the negative charge electron which keep the atom hold together. The number of protons is equalled to the number of negative electrons. Due to which atom is electrically neutral. Almost entire mass is in the nucleus. Most of the atom is empty space.Bohr model of atom states that an atom is made up of three particles electron, proton, neutron. An electron has a negative charge, proton having a positive charge while the neutron has no charge.   Electrons revolve in a fixed energy level donated as 1,2,3,4,5,6 or by letter K, L, M, N, O, P counted from the centre to outward.