ATOMIC STRUCTURE

Wednesday, January 02, 2013    No comments

ATOMIC STRUCTURE

ATOM
Smallest particle of an element which shows all properties of element is called atom.
  Some characteristics of "atoms" are as follows:
  Atom takes part in chemical reactions independently.
  Atom can be divided into a number of sub-atomic particles.
  Fundamental particles of atom are electron, proton and neutron.

CHARACTERISTICS OF ELECTRON

1. Charge: It is a negatively charged particle.
  2. Magnitude of charge: Charge of electron is 1.6022 x 10-19 coulomb.
  3. Mass of electron: Mass of electron is 0.000548597 a.m.u. or 9.11 x 10-31 kg.
  4. Symbol of electron: Electron is represented by "e".
  5. Location in the atom: Electrons revolve around the nucleus of atom in different circular orbits.

CHARACTERISTICS OF PROTON
  • Charge: Proton is a positively charged particle.
  • Magnitude of charge: Charge of proton is 1.6022 x 10-19 coulomb.
  • Mass of proton: Mass of proton is 1.0072766 a.m.u. Or 1.6726 x 10-27 kg.
  • Comparative mass: Proton is 1837 times heavier than an electron.
  • Position in atom: Protons are present in the nucleus of atom.

    • CHARACTERISTICS OF NEUTRON
    1. charge: It is a neutral particle because it has no charge.
    2. Mass of neutron: . Mass of neutron is 1.0086654 a.m.u. Or 1.6749 x 10-27 kg.
    3. Comparative mass: Neutron is 1842 times heavier than an electron.
    4. Location in the atom: Neutrons are present in the nucleus of an atom.

    ATOMIC NUMBER
     
     
    Total number of protons present in the nucleus of an atom
    is called "Atomic number" or "Charge number"
      Since the total number of protons and the total number of electrons in an atom are equal therefore atomic   number may also be defined as:
    "Total number of electron in an atom is called Atomic number"
      SYMBOL: It is denoted by "z".


         
    MASS NUMBER

    Total number of protons and neutrons present in the nucleus of an atom is called "Mass number".
      SYMBOL: It is denoted by "A".
    SYMBOL OF NUCLEUS

     A nucleus is represented by the symbol :
    zXA
      Where X= symbol of element (Cl, O, H , Na etc.)
      A= mass number.
      Z= atomic number.
      1H1, 11Na23, 17Cl35, 7N14, 13Al2 
     

    Read More
    Subscribe to: Posts (Atom)