The document discusses the historical development of atomic models from ancient Greek philosophers to modern atomic theory. It outlines key atomic models proposed by scientists like Dalton, Thomson, Rutherford, Bohr and Chadwick and the discoveries they made about subatomic particles like electrons, protons and neutrons that make up the atom. The modern atomic model consists of a nucleus containing protons and neutrons surrounded by electrons in designated orbitals.

1. THE HISTORICAL DEVELOPMENT OF ATOMIC MODELS SCIENTIST PROPOSAL ATOMIC MODEL ____________ 2.2 THE ATOMIC STRUCTURE __________ __________ (1766-1844) The ___________ basic __________ of all matter is called ___________ Atoms are thought to be __________________ like very___________________ Atoms cannot be ____________ into smaller particles or be __________ Atoms of a given element have ___________, ____________and _______

2. THE HISTORICAL DEVELOPMENT OF ATOMIC MODELS SCIENTIST PROPOSAL ATOMIC MODEL ______________charged sphere _________________ charged electron ______________________________ (1856-1940) _____________ are discovered Electrons are _______________________________ and are embedded in a ______________________________________

3. THE HISTORICAL DEVELOPMENT OF ATOMIC MODELS SCIENTIST PROPOSAL ATOMIC MODEL Nucleus containing _______________ Orbiting ________ _______________ ______________________ (1871-1937) ________are discovered Protons are __________ _______ and form a part of the __________, the_____ ______________________ region of an atom Nearly all the _________ of an atom is ___________ in the _________________ Nucleus surrounded by _____________ travelling through ________________ than nucleus space

4. THE HISTORICAL DEVELOPMENT OF ATOMIC MODELS SCIENTIST PROPOSAL ATOMIC MODEL ______________________ (1885-1962) _________________ are discovered ___________ travel only in a certain _____ ____________ around the ______________ of nucleus called the ___________________

5. THE HISTORICAL DEVELOPMENT OF ATOMIC MODELS SCIENTIST PROPOSAL ATOMIC MODEL PROPOSAL SCIENTIST PROPOSAL ______________________ (1891-1974) _____________ are discovered Neutrons are __________________ in the ______________ of an atom The mass of a ____________ and a _________ is almost the same

6. THE MODERN ATOMIC MODEL Improved model proposed by ________________________: An atom consists of a ______________ and _________ that move around the _____________________ The ___________ is _______________ and occupies a __________,_______________________________ The _____________ consists of __________________________ and __________________________ The ____________ move rapidly around the nucleus in the region called _________________________

7. SUBATOMIC PARTICLES OF AN ATOM

8. PROPERTIES OF SUBATOMIC PARTICLES Have ___________________ and ___________________ _______________________ are found in the ______________ of an atom while __________________ surround the nucleus Most of the ___________ of an atom is concentrated in the _______ ( mass of _____________________ greater than mass of ___________________) An atom consists of an __________ number of ___________ and ___________ ________________ of an atom is ____________ PROTON Symbol: _____ Relative electric charge: ____ Relative mass: ______ ELECTRON Symbol: ______ Relative electric charge: ____ Relative mass: _________ NEUTRON Symbol: _____ Relative electric charge: ___ Relative mass: _____

9. PROTON NUMBER AND NUCLEON NUMBER PROTON NUMBER : Number of __________ in its ___________ ___________ number of ___________ and ____________ in its atom So, NUCLEON NUMBER : NUCLEON NUMBER : +

10. SYMBOL OF ELEMENTS Atoms from _________________ have _________________________ __ Each element has a __________________________ Example: * Sodium has proton number ______ * Oxygen has proton number ______ Each element is given a ___________ and ____________ ( See Periodic table) Standard representation: X A Z

11. QUESTION: A sodium has 11 protons and 12 neutrons. What is the proton number and nucleon number of the atom? Represent the atom in the form of z A X SOLUTION:

12. QUESTION: Proton number of hydrogen is 1 and its nucleon number is 1. What is the number of neutron and represent the atom in the form of z A X SOLUTION: