The Structure of the Atom - Chapter 2 F4

1. Matter is anyting that occupy space and has mass.
2. Definitions:
 - Atom - is the smallest particle of an element that can participate in a chemical reaction, tiny and discrete( isolate from one and another)
 - Molecule - is a group of two or more atoms which are chemically bonded together.( covalent / ionic bond )
 - Ion - positively charge / negatively charged particle, ( atom that losing electron > +ve ion / atom that receive electron > -ve ion )
3.  The kinetic theory of matter - discuss the arrangement and moving of particles, the forces of sttraction between particles and the energy content in the particles in the different state of matter.
4. The change in the state of matter is caused by heat supply to the particles.

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the increasing of heat : turn the solid particle to liquid and to solid

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the decreasing of heat: turn the gas particle to liquid and to solid

the heat supply is absorbed by the particle. it cause the particle to move ( vibrate ) faster and overcome the force of attraction between the particles at their fixed positions.. the point where the solid particles become liquid is called "melting point" at this point the temperature is remains constant .

when the heat is released to the surrounding by the particles, ( the cooling process ) it cause the particle to lose their kinetic energy so, it moves slower. The particles then closer and attract to each other to form solid. At the point where the liquid becomes solid is called " freezing point". At this point the temperature remains constant.
5. The atomic structure=
a) John Dalton - a very tiny ball.
b) JJ Thompson- plum pudding model - atom is a sphere +vely charged with -vely charged particles called electron surround it.
c) Ernest Rutherford - atom have a +vely charge at the central region called nucleus with -vely charged particles electron moves around it.
d) Neils Bohr - electron moves in an orbit called shell.
e) James Chadwick - neutron gives half of the mass of atom and exist in the nucleus.
6. Subatomic particles of an atom=
a) Proton - relative electric charge = +1, relative mass 1
b) Neutron - relative electric charge = 0, relative mass 1
c) Electron - relative electric charge = -1, relative  mass 0.0005
7. Proton + Neutron = Nucleon , in nucleus of atom
8. Definitions =
 a) Proton number = is the number of protons in its atom
 b) Nucleon number =  is the total number of protons and neutrons in its atom.
9. the different proton number shows the different element. refer to the periodic table and make sure you enable to write the symbol of the element and their respective proton number and nucleon number.
10. the atom of the same element with different neutron number is called isotopes. examples are ; for Oxygen, O-16,O-17, O-18, or for Carbon, C-12, C-13, C-14.

11. Isotopes

1. Isotopes are atom of the same element with same number of proton but different number of neutrons.
2. Isotopes are atoms of the same element with same proton number but in different nucleon number.
3. Example :

1   H 1	2   H 1
Nucleon number = 1	Nucleon number = 2
Proton number = 1	Proton number = 1
Number of neutron = 0	Number of neutron = 1
-         Hydrogen -1 and hydrogen-2 are isotopes . Both have the same number or the same number of protons but in different in nucleon number because of the difference in the number of neutrons. -         Isotopes have the same chemical properties but different physical properties because they have the same electrons arrangements.

4. Uses of isotopes

i-                    Medical field          

-           To detect brain cancer

-           To detect thrombosis ( blockage in blood vessel ).

-           Sodium-24 is used to measure the rate of iodine absorption by   

            thyroid gland.

                  -           Cobalt-60 is used to destroy cancer cells.

                  -           To kill microorganism in the sterilizing process

ii-                  In the industrial field

-                     To detect wearing out in machines

-                     To detect any blockage in water, gas or oil pipes.

-                     To detect any leakage of pipes underground

-                     To detect defect/ cracks in the body of an aeroplane

iii-                 In the agriculture field

-                     To detect the rate of absorption of phosphate fertilizer in plants

-                     To sterile insect pests for plants.

iv-                In the archeology field

-           Carbon-14 can be used to estimate the age of artifacts.

12. Electron arrangement

1. the electrons are filled in specific shells. Every shell can be filled only with a certain number of electrons. For the elements with atomic numbers 1-20 ;

-         First shell can occupy with a maximum of 2 electrons.

-         Second shell can occupy with a maximum of 8 electrons.

-         Third shell can occupy with a maximum of 8 electrons.

b. Valence electrons are the electrons in the outermost shell of an atom.