Friday, October 28, 2011


ISOTOPES : Atoms of an element has same proton number but different nucleon number.

Fact #1 Isotopes mempunyai nucleon number yang berbeza tetapi proton number tetap sama.
Fact #2 Elements yang sama sudah semestinya number of proton yang sama
Fact #3 Nucleon number = number of proton + number of neutron

when nucleon number different (same elements) = number of neutron different

example : carbon-12 and carbon-14

Name of element : CARBON
Proton number    :  6

Nucleon number Carbon-12 = 12
Number of neutron Carbon-12 = 12 - 6    = 6

Nucleon number Carbon-14 = 14
Number of neutron Carbon-14 = 14 - 6    = 8

Conclusion : Isotopes of elements has different number of neutron and nucleon number but same number of protons.


Carbon-14 : Archaeological Dating
This method called radiocarbon dating.
Remembering that the half-life of carbon-14 is 5700 years, then after 5700 years half as much carbon-14 remains within the organism.

Cobalt-60 : to kill cancer cells without surgery

Gamma rays of cobalt-60 are used to kill cancer cells without surgery in patients. This treatment is known as radiotherapy.


Iodine-131 : to investigate the thyroid glands by measuring the uptake of iodine-131.

This tracing method is also used to investigate the thyroid glands by
measuring the uptake of iodine-131.

Phosporus-32 : The metabolism of phosphorus by plants can be studied using phosphate
fertilisers that contain phosphorus-32.

A solution of phosphate, containing radioactive phosphorus-32, is injected into the root system of a plant. Since phosphorus-32 behaves identically to that of phosphorus-31, the more common and non-radioactive form of the element, it is used by the plant in the same way. A Geiger counter is then used to detect the movement of the radioactive phosphorus-32 throughout the plant.

Sodium-24 : to detect leakage of underground pipes.

Used to locate leaks in industrial pipelines, and in oil well studies. 

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