2.3 Isotopes and Their Importance

Isotopes
■ 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, $\begin{array}{c}16\\ 8\end{array}O$	8	8	8
Oxygen -17, $\begin{array}{c}17\\ 8\end{array}O$	8	8	9
Oxygen -18, $\begin{array}{c}18\\ 8\end{array}O$	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.

← 2.2 Atomic Structure

2.4 The Electronic Structure of an Atom →

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