Bihar BoardEnglish MediumSTD 12 SciencePhysicsNUCLEI3 Marks
Question
Explain isotopes, isobars, isotones and isomers by giving examples.
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Answer
→ (i) Isotopes : →The atoms which have atomic number Z same but atomic mass number A different, then such type of atoms are called the isotopes of each other. →For example : Isotopes of hydrogen are ${ }_1 H ^1,{ }_1 H ^2,{ }_1 H ^3$ •${ }_1 H ^1$ - there is one proton but having no neutron. • ${ }_1 H ^2$ - there is one proton one neutron. • ${ }_1 H ^3$ - there is one proton and two neutrons. →Isotopes of carbon are ${ }_6 C ^{12},{ }_6 C ^{13},{ }_6 C ^{14}$ →Isotopes of uranium are ${ }_{92} U ^{233},{ }_{92} C ^{235},{ }_{92} C ^{238}$ → (ii) Isobar : →Atoms having same atomic mass number A , but different atomic number Z are called the isobars of each other. → For example : ${ }_1 H ^3$ and ${ }_2 He ^3$ ${ }_{82} Pb^{214}$ and ${ }_{83} Bi ^{214}$ → (iii) Isotone : The atoms for which the neutron number N is the same but atomic number Z and mass number A are different are called isotones to each other. → For example : ${ }_{80} Hg ^{198} \text { and }{ }_{79} Au ^{197}$ → (iv) Isomer : →The atoms for which the atomic number Z and mass number A are same but their radioactive properties are different are called isomers of each other. →For example : ${ }_{35} Br ^{80}$ contains a pair of isomers.
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