Chemistry Series chapter 2: Structure of Atom

Structure of atom

Basic Details:
(a) The word atom was first introduced by Ostwald (1803-1807) in the scientific world.
(b) According to him matter is ultimately made up of extremely small indivisible particles called atoms.
(c) It takes part in chemical reactions.
(d) Atom is neither created nor destroyed.

Basic Definitions: 
Electron: It is a fundamental particle of an atom with one unit of negative charge (1.6022 x 10-19 coulomb) and negligible mass (9.10939 × 10-31 kg)
Proton: It is a fundamental particle of an atom with one unit of positive charge (+ 1.6022 x 10-19 coulomb) and a unit mass (1.67262 x 10-27 kg).
Neutron: It is a fundamental particle of an atom with no charge and a unit mass (1.67493 x 10-27 kg).

Nucleus: The small, positively charged dense mass (diameter 10-15 m) present in the center of the atom is called the nucleus. 

Extranuclear part: The space around the nucleus, having electrons, is called the extranuclear part.
 
Atomic number: The number of protons in the nucleus of an atom is called its atomic number (Z).

Mass number: The total number of nucleons (protons and neutrons) in the nucleus of an atom is called mass number (A).

Isotopes: They are the different atoms of the same element having the same atomic number but different mass numbers.

Isobars: They are the atoms of the different elements having the same mass number but different atomic numbers.

Isotones: They are the atoms of the different elements having the same number of neutrons.

Wavelength: It is the distance between the two nearest crests or troughs (2).Frequency: It is the number of waves that pass through a given point per second (v).

Velocity : It is the distance travelled by a wave in one second (v or c). Also v = v 1.   

                           In next part we will see all Theorems and Experiments of atomic structure.