Sunday, 4 January 2015

2.3 Isotopes and Their Importance

■ Isotopes

Definition: Atoms of the same elements with the same proton number but different nucleon numbers.

Definition: Atoms of an element with the same number of protons but different number of neutrons.

The animation below shows examples of isotopes.
■ Isotopes of an element

Same chemical properties because they have the same electron arrangement.

Different physical properties due to the different number of neutrons.

This video contains information about isotopes of an element.
■ Radioactive isotopes (Radioisotopes)

Unstable isotopes which emit radioactive rays.

Contoh latihan 2.3(a)
Complete the number of subatomic particles for isotopes of oxygen.
Symbol Number of protons Number of electrons Number of neutrons
Oxygen -16, 168O 8 8 8
Oxygen -17, 178O 8 8 9
Oxygen -18, 188O 8 8 10

The uses of isotopes in daily life
■ Medical

Gamma rays from cobalt-60 are used to kill cancer cells.

Iodine-131 are injected into patients to detect thyroid glands.

Medical instruments are sterilized using gamma rays.
■ Agriculture

Carbon-14 is used to study the path of carbon in photosynthesis of plants.

Pests control by genetic mutation.
■ Industry

Paper thickness control.

Isotopes sodium-24 is used to detect leakage of underground pipes.
■ Archeology: Radioisotope carbon-14 is used to study the age of ancient artifacts.
■ Food preservation: Extending the shelf-life of food by gamma radiation.
■ Food industry: Preventing the germination of potatoes and vegetables.
■ This video contains information about the uses of isotopes.

⇲ For exercise(objective and subjective), download for free on Android OS.

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